PC repair software

I was looking into buying some PC repair software to help keep this computer running at its best. I looked at a few but haven’t decided on one yet. Really don’t know which is better. One that I looked at Registry Clean Fix 2008 said it found 286 problems. The other one RegCure found 986 problems. Thats is a real difference in problems to fix. Does anyone know of a program on the maeket that is reliable and does what it says it will do? Does Tech Rep. know of any that works to keep computers running at top performance? Thanks for the info in advance.