A friend of mine loaded to many programs at one time and now when I boot my cpu it says Explorer has formed in illegal operation and must shutdown

Its going to be fiddly to track down. I think the best bet is to try to restore the registry to a date just before this happened. Assuming you are on W95 or W98 (you didn't state your Operating System) then tap F8 key while booting and choose one of the two command prompt options from the startup menu. Then type scanreg /restore (hit Return key) and you should see your date options. If this works then none of the added on programs will work but the files will still be cluttering up the place. The only answer to that is to install them one at a time then uninstall them (if you don't want them), which will then take the files out too. DerekW

Its also very important to defragment after installing/reinstalling programs. Nowadays especially since file sizes are so large, the HD gets fragmented in no time and blue screens, crashes are frequent.

I doubt very much if fragmentation is the cause of this problem. Rollback the registry or uninstall some programs, as suggested. Defrag later Life is hard; it's harder if you're stupid. -John Wayne