Recently when I booted the computer it refused to boot. Somehow I managed to load a screen allowing me to commence a system recovery, but as a result I have lost all the data on my computer. The various documents and other personal information on the computer does not concern me, as I have a backup of that information. However, I purchased some antivirus software from the internet and do not have another copy of the installation file, so I was hoping that I could recover the antivirus software from the computer?

The screen that you reached allowing for a system recovery was likely a utility which came with your computer, allowing an easy way to restore the system in the event of a hardware failure (or some other need to reinstall Windows from scratch). Most brand-name computers come with a recovery disc, but since you did not mention that you inserted a CD (or DVD) into the computer I envisage that your computer has a recovery partition on the hard drive instead. This is a special hidden partition on the hard drive that stores the recovery data, in lieu of the computer coming with a recovery CD. The advantage of the recovery partition is that you don’t risk losing the recovery CD and it is much more convenient to restore the computer, since you usually just need to tap a hot-key during boot-up to enter the recovery mode (which is likely how you booted the computer into this mode, either intentionally or inadvertently). Of course, the biggest disadvantage is that if the hard drive in the computer fails then it will take the recovery partition with it, in which case you usually need to contact the computer manufacturer to either send you a set of recovery CDs or alternatively a new hard drive with the recovery partition included (if the computer is still under warranty). There is also a risk for the more adventurous users that if you attempt to manually partition the hard drive you could inadvertently wipe the recovery partition from the drive, although this is a less likely situation since those power-users who are doing manual partitioning would usually be knowledgeable enough to identify the recovery partition and that partition alone.

Nevertheless, this has provided some background as to how you reached the current point. I assume that you have successfully recovered Windows and your computer is now back up and running. You are correct in assuming that it is possible to recover data from the hard drive in certain circumstances, although I will say at this point that the recovery of your antivirus software will not be possible (but read on for a more in-depth explanation as to why this is the case). As a starting point we will consider the specifics of recovering any data from a hard drive and then move onto the problems which you could encounter when trying to recover specific programs from a hard drive.

First, let’s look at the process involved in recovering data in general. When you delete data from the hard drive the space which that data previously occupied is marked so that it can be overwritten by new data (when the need arises). Therefore, that original data is still on the drive until it is overwritten by new data at some point in the future. If you can obtain a data recovery tool then, assuming that that data has not been overwritten, you may be able to recover that data. However, if the data has been overwritten, or the drive from which you are attempting to recover the data is severely damaged or corrupted, then you will likely need to send the drive to a professional data recovery specialist who has the tools and techniques to recover data when the situation with the drive is a bit more dire. Additionally, if you have formatted or repartitioned the hard drive (which would have likely occurred when you used the recovery utility to reinstall Windows) then this also would make the file recovery process more challenging, depending on the level of formatting and amount of partitioning that occurred on the drive). As you can probably see, recovering data from a hard drive is somewhat a hit and miss process and you would likely only want to undertake this procedure if the data which you need to recover is absolutely critical and non-replaceable. In your case, it doesn’t seem that it falls into this category since it was a program that you purchased from the internet. In the worst-case scenario you could recover from this situation by simply re-purchasing the software (and while I agree that this would not be the best alternative, the cost of re-purchasing the antivirus software would likely be significantly less than the time and money you would invest in trying to recover the data from your hard drive). In any case, as you will read below even if we could recover the program files they would not be particularly usable, and there is likely a neater and more reliable way around this problem anyway.

Given that you have reinstalled Windows on the computer it is unlikely that you would be able to easily recover the data since (at least) portions of the antivirus program data would have probably been overwritten during the Windows reinstallation and subsequent usage of the computer. However, if by some miraculous means you were able to recover the folder containing all of your antivirus software files (e.g. C:\Program Files\My Antivirus Software) then there is a good chance it will not work. When Windows software is installed not all components of the software are neatly installed into one specific folder, but some shared files and information will instead be placed in other locations on your computer (such as in the Windows system directories, Windows registry, etc.). These files and data items are essential for the program to run, so without them it is likely the program would not even load. Therefore, if you were to recover the program directory when you attempt to run the antivirus program it would try to find those shared files, be unable to find them and then either produce an error or just refuse to start. This is why when Windows software is being reinstalled you need to do a proper reinstallation using the original installer, rather than simply copying the program directory.

From your question it is apparent that you do not have a copy of the installation file, which is an obvious problem. However, most antivirus vendors who allow you to purchase their software online keep a record of the purchase so that, should this exact situation occur, you can logon to their website and download a new installer and a backup copy of your licence. When you purchased the software it is likely that you created a username and password so that you could complete the purchase. These credentials should also be usable to logon to their website to view your purchases and download the relevant installation files. If you are unsure of your username and password then you should be able to click the “Forgot” link on their logon page, enter your email address, and their system can email you these details. Once logged in you should be able to view a listing of the items you have purchased and download those purchases.

Should all else fail, you could always re-purchase the software. As we discussed, this is not necessarily the best alternative but since we have established that you would be unable to recover the program from the hard drive, and you are not able to re-download the software and licence from the vendor’s website, you have no other options at this point. In any case, once you have a copy of the installation file and licence information, make sure that you take a backup of these items just in case this situation arises again!