Msi kt4av bios-altered clock speed and com not opening to post

[Gaarry MAc]

Hi. I got an MSI KT4AV motherboard today and fitted it with an AMD Sempron 2400 CPU and altered the cpu frequency from 100MHz to 166MHz. This was so that the CPU would function at full speed of 1.67GHz. It wouldn't do this in the AM37 mobo i had in my Compaq Presario S3010AN which saw the CPU as an AMD Athlon XP1500+ and its speed was 1.33GHz. The AM37 only has two FSB settings, 100 and 133. Neither gave me the necessary frequency to push the Sempron to DRAM 333 and the 1.67GHz I wanted.
This worked perfectly, until I thought I'd try to push it to 2GHz and raised the CPU frequency to 200. I didn't alter the multiplier and left it set as it was, ie. Auto.....I presume this was x10.
Rebooted computer and , yep, a black screen, then a screen that said " No Signal".
Checked the CPU, RAM (2GB PC2700 DDR SDRAM) and Graphics card ( Radeon 9000S) back in the AM37 mobo and thats all good there.
I guess I have stuffed up the bios settings and am locked out.
I have tried to get the bios back to default by removing CMOS battery for a while and shorting the clear bios pins with the jumper moved to pins 1-2.
All no good.
I'm about to download a new bios ( v 5.4) for the mobo (MSI KT4AV - MS-6712 VER:10A) and try to load it to the BIOS, but....yep...how can I do that if the computer will not so much as go to POST?

Ideas please, thanks.
Garry Mac

 

[Unolocogringo]

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.

 

[Gaarry MAc]

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