Hi Deckie28,
For someone with little knowledge of computers, and for free, I'd recommend
Benbyrd's suggestion of CCleaner at
CCleaner - Home .
Otherwise, one of the programs I use, at
Registry Cleaner from RegistryOptimizer.com
For $29 it's a dead simple program without any confusing bells and whistles, and it works.
Good luck,
Dickiesam