Error loading operating system??

I just put together a system with a new MB (Asus A7V400 MX) but had to use an older processor (Athlon 700) and newer memory (DDR2700) I know, a pretty crazy config but it's just for testing purposes to verify I can get the thing to work correctly. The system boots up fine and all of the devices are detected correctly but the minute XP starts to load it takes me to the load menu complaining about the hardware change (OK, fair enough) so I choose "Safe Mode" to get rid of the old drivers. It begins to load and then, bamm! Blue screen - Stop, error 0000007e and it starts complaining about hard drive controllers and what not. So I decide OK, I'll just try a new HD and start from scratch. Windows loads the first part and then, upon reboot I get a different error - "Error loading operting system". Could it be that the memory/processor combination is just too wierd for the system or am I just stupid and should have known better than to try what I tried. Can you actually use memory that fast with a processor that slow? Thanks!

In your bios there is a setting to reset configuration data.

Once done it will revert to no by default.

The system may be looking for older components there before, clear the bios and reset all the settings and have another go at it.

The memory will run at whatever the board will let it, it's ok, say it's set for 2100, and you put 3200 in it, the memory will only run at 2100, a waste of good memory speed but not a problem.

The error loading operating system may be as simple as having the boot order set wrong, check it.

The processor/memory combination should be fine provided that the board supports both. Note I said should... stranger things have happened than incompatibilities between processors and memory sticks.

When installing a new motherboard, one should really install the Operating System fresh, especially since OSes like Linux require different kernals for different processors and such. You might not be able to recover Windows on a new board because recovery assumes that all motherboard drivers are in place and correct, so there may be some incompatibilities between the ones installed and the new motherboard.