Just a thought.

[Scarecrow28]

There are so many downloads for sale out there, some free and some for a fee. To keep one's PC Virus protected, firewalled, replace memory, and dozens of other things to keep a comp. healthy. Most advanced users do this themselve's without these programs, knowing that a lot of what these programs are offering are already in your comp. If you use any of these and want to undownload the program for whatever reason, some of the original files you need can also disappear as a lot of these files are used by these programs. That is why a backup Disc is so inportant.
There are some excellent and very helpful downloads out there,and before I used any, I would ask about it here.As from reading the posts there are some very advanced users here.

[Toyotathon]

Very good advice - Mr. Scarecrow!

[Bond]

I think "snapshot" software is also becoming increasingly popular, mostly because of the issue you describe, Scarecrow. There are just too many apps that do NOT uninstall everything they've installed. So, you're left with random files in your <windows>/<system> folder or elsewhere. Worse, you've unknowingly installed some kind of monitoring/spying/tracking software that is INTENDED not to remove itself.

I agree with you, Scarecrow that asking around is always a good idea before installing new software. I would add that having a good snapshot, backup, virus protection, and ad-removing software (i.e., Spybot) is also a good idea before installing ANY downloaded apps.