how can i clean windows vista home registry.because i kept installing programs and uninstalling them and some didnt uninstall right

Virus protection?

I really want good virus protection, so can anyone tell me which company or software is good please. =]

System restore doesn’t work, I do not have a prior restore point and I need to remove/change some registry values. I found what to change and what to delete but the directions tell me “restore registry entries to their previous values” what does this mean? Is there a site where one can find what the registry values were?

I am starting a Tech Support business and was wondering if anyone knew soft ware I could use to test and hardware and other things either from software built into windows (vista or xp) or third party soft ware (cheap or free). Or if anyone else does this what do you use?