No Keyboard detected on boot!!

P5B-D bios 1237
core2duo E6300 @ 3.3
4GB DDR2 2x2GB
GTX 260
Windows XP SP2


I was running some OC tests, set my memory timings to 5-5-5-18-6-42 5-12-5-12 then booted to 470*6 in windows (i left both ram sticks in). I would like to point out that 475*7 1:1 was memtest and orthos stable, i was pushing the FSB.

Then i ran setfsb and increased the fsb to 480 which worked (it was expected), then tried 490 and my system froze.I did a reboot and tried the same thing but this time i ran memset first, selected a tRFC of 54 then hit apply, ran setfsb to 490 and my system froze again and i got a high pitched noise coming from my speakers.

On reboot it looks like the bios can't detect my regular PS/2 keyboard anymore, so i had to dig out my old wireless usb keyboard (wireless kb >> usb hub) and im using that right now, but i can't access the bios using that keyboard?

When i turn the PSU off then on all 4 leds on my keyboard flash, but only 1 led stays on when booting,where all 4 leds usually flash on boot.

I fear if i clear cmos back to stock i might not be able to get in bios using my PS/2 KB anyway, and end up stuck with an underclocked system?

how can i fix this?

I removed the cmos battery and moved the jumper for 5 minutes like suggested , and im happy to say my KB came back to life.. i also enabled usb legacy support in bios, so im good now.