PC diagnostic/tweaking sites

[kriskwery]

In trying to answer another question on AB, I discovered the existence of several free sites promising to optimise various things on my computer.

Can anyone advise whether these are kosher or am I likely to be creating more problems than I solve?

I am very scared ..................... ! !

(I've just had a quick look at PC Pitstop, Uniblue at http://www.liutilities.com, and failed to raise cybertweak.co.uk. Any comments/other suggestions? Feedback much appreciated)

[Oneeyedvic]

I've used pcpitstop several times and find it fantastic - I've also used it to help solve virus problems for my friends