I built a few boxes a couple of years back using that board and had a similar problems whenever the power went out (even with the comuter off). I'm assuming that you have the A7V133 flavor.
The board is a jumperless board and you shouldn't have to mess with any of the jumpers it to reconize the cpu. Just go into the BIOS, select the advanced menu and on the CPU speed choose the 1200MHz option and you should be fine.
For whatever reason when you change the processor on that board, the BIOS will always underclock it for a "safe" mode until you manually go into the BIOS and set it correctly.
Should you feel the need to overclock or do it the hard way, you can find the jumper settings on page 18
here . I perfer the easy way in the BIOS though

.
Mike