No Video on boot

I have an ASUS p5vdc-mx Ver. 2

When first installing the system i ran into a problem where i could not get video from the AGP so i took it out and tried the on board. That only worked about 1 out of every 5 times. So i figured to try and flash the bios, i never was actually able to flash it but one of the times i was able to get video i went ahead and installed XP pro on the system. Then tried the AGP and it worked perfectly! For a month, untill a few days ago we tried to bring it up again and no video, i tried the on board and it worked (the first time) then went intermittent again, Once i got into windows i used the Asus Update utillity to flash the bios to the most recent version since i was unable to flash it from floppy on boot up previously and Still no video and it has gotten worse i can only get video about 1 out of every 10 times when booting, dont know why. I am thinking a bad board but why does it work sometimes and not others. when i do get video sometimes it just freezes at the POST screen. But when it does come up and woks i get one of three errors

1.Bad Checksum
2.Overclocking Failed
3.New CPU speed

F1to enter setup
F2 to continue and load defaults

The thing is i never set up to overclock. I am lost, any ideas.