Spontaneously, F, P, and Z characters appear in the middle of typing. For example: FPFFFFFFFPZFFFFFFFFFPZ. The letters may appear in upper or lowercase, and spontaneously. They appear to be related to the location of the cursor, and sometimes appear during a pause in typing but not always. The computer is running Windows Vista Ultimate.

It is not surprising that the text appears depending on the relation of the cursor, as the cursor will be providing the point at which the text should be inserted. This indicates that for some reason the computer is thinking that keystrokes are being sent and typing them into the document – in other words, from the perspective of the computer there is nothing different between the random characters appearing and you typing something on the keyboard. The simplest explanation for this problem is that something is physically wrong with your computer keyboard, such as a key on the keyboard becoming stuck (which could explain why this only occurs when you pause in typing). Alternatively, there could be something wrong with the logic on the keyboard itself (as most modern keyboards have on-board circuitry, and some even have a limited amount of memory which stores firmware – a bit like a very light-weight operating system for the keyboard). To test the theory, connect another keyboard to the computer to check whether that resolves the problem. Hopefully you should be able to source a keyboard from family or friend which you can use for testing. Alternatively, if you simply want a cheap keyboard to test, then some stores and computer fairs sell very cheap keyboards for around $5. These are not particularly good quality (as the price implies) but could be an inexpensive way to test whether this is the problem (although, if you don’t have a spare keyboard then you may wish to try the other troubleshooting steps below before purchasing a test keyboard). Should you find that the problem does not occur when a different keyboard is connected then it’s fair to assume that something is wrong with the keyboard and it should be replaced.

Unfortunately in most cases the problem is not necessarily this easy to solve, so if it’s not fixed after swapping keyboards then we need to look elsewhere for an explanation. Next, assuming that you are using a USB keyboard, try connecting the keyboard to a different USB port. This is a long-shot, but we should check that the problem is not related to a faulty USB port on the computer. I suggest that you connect the keyboard to a USB port that is likely to be on a different USB controller, to eliminate the possibility that there is something wrong with the controller itself. By way of background, USB ports on a computer are connected to a USB controller (which contains all the logic to send and receive data across the USB ports). While multiple USB ports can be connected to one controller there are generally multiple USB controllers in the computer, otherwise bottlenecks can occur if too much data is being sent through a family of USB ports on a single controller. Generally the USB ports on the front and back of the computer are on different controllers, so if the keyboard is currently connected to ports on the front then I would suggest you switch them to the ports on the back.

If you find the problem is resolved then there could be something wrong with either the USB port or the controller. As a final test, connect the keyboard to a different USB port on the same controller. For example, if the keyboard was originally attached to a port on the back, switch it across to another port on the back. Be aware, this does not guarantee that the other port will be on the same USB controller (as this is difficult to determine without opening up the computer) but if the ports are next door to each other then it’s a fair bet they will be on the same controller. If the problem does not occur, then the problem is likely limited to the original USB port. In this case, leave the keyboard connected to a different USB port and keep in mind that the port is potentially faulty (in case you are thinking about connecting another device to that port in the future). Should the problem continue then there is probably something wrong with the USB controller. In this case, switch the keyboard back to a working port on a different USB controller. It’s likely that you have other devices connected to USB ports on that potentially faulty controller. They may work correctly, as it might just be keyboards which have problems. However, it would be worthwhile keeping this in mind should you find that other devices connected to USB ports on that controller exhibit strange behaviour.

Should changing the USB port to which the keyboard is connected not resolve the problem, we have eliminated hardware as a possible fault and will now move onto possible software-related causes. The first is that you simply have too many background programs and processes running on the computer. Previously I have found that when you have too many things running in the background, the computer can become quite lethargic to respond and this can cause particular keys on the keyboard to become “jammed” on and repeat themselves, especially if you have been typing very quickly with the computer being slow to respond. To test this theory, don’t run any non-essential programs on your computer (e.g. email clients, web browsers, etc) next time you are typing in a document to check whether the problem occurs.

If you find that the problem does not occur then there are actually two possible explanations. The first being that the computer was becoming overloaded and slow to respond, and by not running the non-essential programs you freed-up sufficient resources to make the computer more responsive. Alternatively, it is possible that one of the programs which you closed was conflicting with the system and causing the problem. Therefore, we need to conduct some additional troubleshooting steps. Be aware, if closing the various background programs did not fix the problem you should continue with this procedure anyway, since it will involve closing all non-essential background programs and processes (even those which are invisible to the user) and therefore is a much more comprehensive version of the procedure which you previously attempted.

First, you should close all running programs on your computer (including those in the system tray, next to the clock). Don’t worry if you are not able to close some of those processes – they will be closed in the next step of this procedure. Once all of the visible programs have been closed we will proceed to close the invisible background processes and other programs that you may not have been able to close in the previous step. Press CTRL-ALT-DEL to show the Security Manager. Click “Start Task Manager” and the Windows Task Manager window should appear. Click the “Processes” tab which will show all processes running on the computer. Ensure that the “User Name” column is showing – if not, go to the “View” menu > “Select Columns” and tick “User Name”. Click the “User Name” column heading to sort by that column. This is important, as we only want to end processes that are running under your own user. You can now proceed to close all the processes running under your user, except “explorer.exe” (which is the Windows graphic user interface) and “taskmgr.exe” (which is the Windows Task Manager – the program we are currently using to close all of the processes). To end a process, select the process in the listing then click the “End Process” button and confirm in the confirmation message that appears. Once all the processes have been closed (with the exception of the two mentioned previously) close the Windows Task Manager and then open a document and check whether you can type without having the random characters appearing.

If all now appears to be normal then it seems that one of those programs or processes is causing the problem. At this point it is just a process of elimination to determine the root cause. Restart the computer, so that all the background programs and processes reload, and then selectively start closing the background programs and processes (using the same procedure as above) but each time checking whether the problem has stopped. This will be a fairly time consuming process, but when the problem stops you know that you have found the problematic program or process. At that point in time note down the program or process name and then conduct some research on the internet to find whether this is a known problem and whether any fixes are available. If you get stuck and are not able to find any useful information then please send this information through to me and I will also investigate to check whether there are any known issues with that particular piece of software which could be fixed through a workaround or update.