I am upgrading my home built PC with the following:
ASUS P7P55D-E MB, Intel i5-750 Lynnfield 2.66, 4 gig RAM. I recently heard about having to make sure what your MB will handle in HDD capacity. Never heard this before so I am checking ASUS specs for this info but cannot find it. Also, please explain why this is an issue.
That's really only a limit with older boards. You should have no trouble with that ASUS board and any current Hard Drive, even a 2TB one. Now if you want to use multiple hard drives in a RAID array, there is a 2TB limit as far as the Boot partition goes and that's due to the limitations of BIOS.