I have a Packard Bell Imedia and have replaced the motherboard that blew with a Gigabyty GA-8I915PMD. Memory was upgraded to DDRII as required by the motherboard.
When the machine boots up it stops at the memory test. The keyboard appearn not to work as you cannot enter the bios [F2] or [F8] yet. About 10 minutes later the machine contiues to boot as normal You ca enter bios at this point if required.
All hardware and software runs normally when system fully booted.
Try disabling memory test in bios and see if that clears the problem. If it does then there appears to be something about your memory that the bios does not like or it would go through the check fairly quickly.