First unplug or turn off the power supply.
Then reset the bios. Some boards will not reset if you have power from the power supply.
I tried that yesterrday but will try it again shortly. Thanks for your reply Rick
Well, today I moved the bios reset jumper from pins 1-2 to pins 2-3 and replaced it to pins 1-2 hours later. Thought I had done that the other day. obviously hadn't, must have removed the cmos battery only.
All is back to normal now and I don't think I will try to get a bit extra out of the cpu 'til I know what I'm doing.
Thanks again to you Rick for the prod in the right direction