Been there and done that ......... twice! I found a lovely PC guy (not Politically Correct but good with Personal Computers). He was personally recomended to me when my computer allowed me to switch it on and then leave enough time to make a cup of tea and do the crossword before it was running
He doesn't advertise but is a retired gentleman who is recommended by past customers.
If you can find a genuine person to 'clean' your PC and load some decent anti spy-ware along with the usual stuff then your computer will be like new
I paid £35 for the first hour and then a nominal fee for anything that couldn't be done within the hour ..................... my hard drive went to hospital for a night and was returned the following day and reinstalled with lots of freebees for about £70. It was like having a new computer again and well worth the money spent