|You could check out the PC Pitstop website. I think they have a few online tests for scanning your computer, including one for optimizing speed.|
It's really tough to say though, so many factors can slow a PC down. Is this a recent problem or something that has only just developed? If it's a hardware problem, it will probably have been slow from the start. If it's only just started happening, probably gonna be a software issue. A 2.2 performance rating is definitely low though so something must be going wrong!
The Definitive Guide to Registry Cleaners &