Best hardware diagnostic tool

[smurph]

I am having various issues with PC, freezing (with high CPU speed), noisy fan st start-up, failing to boot...can someone let me know best diagnostic tool to use to assess, and.or to continue to monitor....

 

[Joe C]

I don't think there is one tool to do all, but the Ultimate Boot CD has a good selection all on one bootable disk

Ultimate Boot CD - Overview