Try a different slot and if the problem continues you could try a BIOS update:
1) Turn the system off
2) Remove all the peripherals (keyboard, mouse and cd, DVD drive)
3) Remove the BIOS jumper from the board
4) Load the BE0028P.BIO file in an empty flash drive hopefully no bigger than 2g and connect it to the back panel of your board
5) Turn the system on and wait for 10 minutes until you see the BIOS update screen.
6) Then boot to the BIOS and check the latest BIOS version was loaded correctly.
You can get the latest BIOS version for the following link: