Hi Steve,
The fact of the matter is - ask anyone of the staff members here, and they'll say I know alot. Ask me personally. I'll say I know jack ****.
And don't worry about getting laughed at...being an IT technician is all about being wrong most of the time...no 2 errors are exactly the same...they may have the same error number..and the same resolution...but might have different circumstances.
A format is good for 1 person - and not good for another -
never rely on this as your first and only tool to fix a problem.
In regards to the best software...it depends on what's wrong

Virus - I find that the Prework steps we have here is the
best way to clean a computer...there is no such thing as an All-in-one wonder program that will do as good of a job (as ladygreenwitch will agree with me).
The best way you can make sure that a computer has no troubles...is make sure it's 100% up to date with windows, and schedule a defrag every week. If the user doesn't keep going to bad sites - then you won't need to worry about virus scans for more then once a month as a general check.