This is sometimes attributed to viruses, but it isn't always the cause. Try to download this zip file and extract it. If you can't, let me know what happens and we'll go from there. http://www.dougknox.com/xp/fileassoc/xp_exe_fix.zip
If you can extract it, double click on the xp_exe_fix.reg
file and when prompted on whether you wish to merge the information to the registry, say yes or click OK to proceed.
Try opening a program like IE.
Post back with details of any error messages (exact messages are helpful if you can write them down) you encounter.
Once we get you set, we can run scans to ensure we catch any infections that may be present.
Edited by Galadriel, 24 August 2010 - 03:21 PM.