I think it's time you took a hollistic approach to your PC problems.
You've spent a lot of time working on eliminating spyware and protecting it from viruses but when was the last time it got to really kick back and relax? Have you taken it out for a night on the town lately? Have you told it how much it's been appreciated? And most importantly, when was the last time that thing got laid?
Computers have become very sophisticated nowadays. You have to care for their emotional needs as well as their programming needs.