i've got a 800mhz celeron,with packard bell houston3+ motherboard,with 64mb(133mhz)ram ,100mhz bus speed.tried to upgrade to 256mb,didn't work.shop said try branded ram(dearer),didn't work.shop said try 128x2.this started but only reads 128mb not 256mb(64mb each slot)????any ideas,do i need to change jumpers,settings??packard bell doc. sez that u can upgrade to 256mb(64mbit)or512(128mbit)...assymetrical ram???