the problem may be lack of power..
i have 256MB ram each simm has a tolal of 16 chips..32 counting 256MB..
this is a heavy drain on the 5v line..which can lead to lock-ups when useing 68k & ppc chip at the same time..
also clean the contact.
also when inserting simms try inserting a little to to left or right as the contacts may be dirty..
simm socket may also need cleaning..
