This seems to be very widespread problem (22K results in Google!), & 'faulty' RAM isn't usually to blame as such.
Here's a related search on the Microsoft site click here - something there might give you a few things to try.
One person on another forum suggested these as a possible fix (re-worded to make better sense): - Remove & reseat the RAM modules - Try with only one module at a time - Check RAM voltages in the BIOS, & set to correct/default ones if different to its specs - Check RAM modules against the manufacture's compatibility list for that particular motherboard - Try another brand of RAM if possible (to rule out a possible compatibility problem as above) - Try with another working PSU, & a more powerful one if possible. Wouldn't recommend buying a new PSU, so try to borrow one off a friend/neighbour perhaps.