I've seen this problem when there is a Hard Drive (HD) bigger and greater than 60 gigs. Why you ask, cause the BIOS is only able to read and handle 60 gigs to run comfortably.
For instince, about 5 or 6 years ago, BIOS manufactures were having problems with HD's larger than 2 gigs. You had a choice, either have one large drive with no partitions or have multiple partitions of 2 cause the BIOS couldn't understand one larger partition and one small partition.
As you noticed, manufactures have overcome that obstacle. But with today's BIOS being so diverse, its able to recongize and work at different levels. Having one large drive or having multiple partitions, today's BIOS can work with them all. Unfortunatly, we are still at a limitation as before. If you have a 160 gig HD that's not partitioned in any way, then you might have some problems. I had a 200 gig that was giving me problems every month. I kept getting BS and system logs didn't help any. There is a problem with XP as well managing Page Swapping and memory with a HD that big.
Actually, anything over 60 gigs, you might have problems later on that's not partitioned. Its best to partition a HD at 60 gigs and less. XP, large HD's, and todays BIOS is reason enough to partition your HD. You don't want to be in the situation where you have a BS and no extra HD's around to back up your data to.
Check for an updated version of the BIOS, test your memory to make sure it's not faulty, and check your HD for bad sectors as well.
