Be cautious
I’ve been very guilty of committing this mistake. It also doesn’t help that I am a little bit of a neat freak (or is obsessive compulsive/anal retentive a better term?). I often make changes to my PC in attempt to organize files and programs. Now there are times that what I’ve done actually can’t be undone. This proves to be pretty frustrating at times.
The best way to prevent this problem is of course – practicing caution. Record old settings and save old drives before changing settings and installing new drivers. If you have enough space, then do not delete old files if you plan to replace them. What I do is actually make an “Archive Folder” where I move my old files. I know a friend who simply modifies the names of old files to differentiate them from the replacements.
Of course, don’t forget to back up everything, twice!