When you go to the GeekSquad at Best Buy they charge atleast 69 or up to 200 dollars in some places for a diagnostic and all they do is run some software that finds out where the problem is. I don't have that kind of money and I need a way to find out what is wrong with my computer whether it be a software or a hardware issue.

So I need to know what is the name of this software or anything similar to this that can check both hardware and software issues.

I need diagnostic software and / or hardware to trouble shoot computer hardware and software issues on PCs. I'm looking for any suggestions for what package to get,
I am currently using Window XP, and trouble shoot problems for my family that use a variety of Windows O/Ses