I recently performed a scan with NAV 2005 and Spybot, and removed all dubious files. The O/S is Win98SE which I use to write programs in QBasic. I now find that when I open the folder in Win98 each *.bas file has an ? on it. If I click on the file to open it a message appears 'This is not a recognised windows file or it has been corrupted'. If I run the Qbasic program it sees all the files and opens them and runs quite normally. The same applies to the files on a backup disk. If I put the back up disk on another m/c everything works fine, so I assume there is a problem with the Win98 program itself. I thought of reinstalling Win98 but is there any program I can run to see if there is any corruption in the program and fix it. Can anyone please help ?