When starting the computer a message appears saying ‘RUNDLL32 caused a page fault in module (unknown) at 0000:009c4068′ followed by ‘This program has performed an illegal operation and will be shut down’. After closing this message, the desktop and icons appear with another message: ‘ALEVIR has performed an illegal operation and will be shut down’. The computer then completely hangs and nothing else can be done. How can I fix this problem so the computer is usable again? The computer is running Windows 98 SE.

There seem to be a few problems on Windows startup, relating to processes crashing on startup which are causing your computer not to boot correctly and then freeze. The most concerning of these messages is the one pertaining to ALEVIR, as this is the name of a process for the Opaserv-A-Worm virus. Since this is the process that crashes directly before the computer hangs, this is the process likely to be causing the problems. Therefore, the first order of business will be to remove the ALEVIR threat. First, we will need to make the computer boot successfully so we can scan the computer for viruses. To do this, you will need to boot into Windows Safe Mode, which is a special diagnostic mode of Windows which does not load any non-essential programs or processes, and will hopefully not load the processes causing the computer to crash. Start the computer, and when the ‘Starting Windows 98′ message appears (just before the Windows splash screen) start tapping the F8 key. In the Boot Menu, select ‘Safe Mode’ and press ENTER. Hopefully, Windows should boot without any problems or error messages that you have previously experienced. Once Windows has booted, go to the ‘Start’ menu > ‘Run’ and type ‘msconfig’ (without the quotes) and click OK. In the System Configuration Utility window that appears, click the ‘Startup’ tab. This lists all programs and processes which load on Windows startup. Note which items are currently ticked (as you will need to re-enable these later). Then, untick all non-essential items. You should be able to untick all items except ‘SystemTray’ and ‘Explorer’ (if they are present in the list). Once this is done, click OK and restart the computer. Since all non-essential processes have been disabled, the computer should load without encountering the errors. Connect to the internet and, if you already have antivirus software on the computer, update the software with the latest virus definition files. However, if you do not have any antivirus software then visit free.grisoft.com and download AVG Anti-Virus Free. This is a free virus scanner which supports Windows 98 SE. Once downloaded and installed, update the virus scanner. Then, disconnect from the internet and run a complete virus scan of the computer. Should any threats be detected during the scan, take the appropriate corrective action to remove the threats. Once the scan has completed, restart the computer. We now want to re-enable the processes which were previously disabled, but not the ones which were causing the errors (particularly the RUNDLL error). Go back into msconfig and re-enable one of the processes which you previously disabled, and then click OK and restart. Assuming the computer comes up again without errors, go back into msconfig and enable another process and then click OK and restart. This stage-by-stage approach to re-enabling the processes will help identify which process is causing the error message(s) to appear. When the error message(s) start to appear again, you will know that the most recently enabled process is the cause. So, you can leave that process disabled to stop the errors appearing in the future.