RAM

My ASUS Terminator P4 came with a 256 MB DDR DIMM installed (unbuffered non-ECC PC2100/1600). I recently add a similar module (different brand of course). Since then, most of the times, on Win XP start up, a blue screen appears but only but such a short time that's impossible to read what's on it and then the system is restarted and form there on everything works pretty well. Should I adjust something in the BIOS (SDRAM Configuration or something)?
Thanks


Julio