Second Hard Drive doesn't show up in BIOS...(again)

hello everyone ^^ i have a problem with my second hard drive. my main/master hdd is a MAXTOR STM380215AS ATA with windows 7 and my second/slave it's a ST3250319AS ATA 250GB (i think T.T) windows XP Professional My second HDD it's newer then my maxtor(3-4 years) but the Seagate sometimes will not show on bios or anywhere else.this happened several times since i got it.. how i solved the...