If your computer is slower than it used to be, if you get errors, if you suspect a virus, trojan,etc....Here is a solution for windows: Go to Safety.live.com.....When you get there select full scan. This is a free search and destroy program from Microsoft, it will scan for virus, edit register, defrag, compress and tune up your computer. It will make a huge difference in performance. I just ran it and WOW!!!!