500gb sata hd. Running winxp pro. Everything runs fine. Problem is winxp does not show full hd storage capacity/size.

You didn't indicate what Service Pack you are running with XP Pro.

http://support.microsoft.com/default...b;en-us;303013

im running sp 2 and 3. xp disk manager shows the drive as 127.99gb NTFS and 337.77 unallocated.

try using some partitioning software, such as Gparted ...the windows disk manager is not a powerful tool...

These numbers can be misleading.
See here for clarification:
http://www.t1shopper.com/tools/calculate/

Thats true hughva, but not in this case, here a 500GB drive is showing at the 127GB Barrier.

My guess is that this drive was set up in a XP system prior to SP1 (or 2000 prior to SP3).

how can i get the hd to show all 500gb whithout losing current data. Or do i live with it and partition the last 337.77gb?

I see you've edited what you see in disk management, this changes things (for the better). Just partition and format the 337 and just use it as extra space.

Or you can use gparted to grow the current partition by 337 or whatever the drive capacity allows.

Actually, doing it this way is the better of the 2 ideas. Leave your "C:/:" @ 127 GB, and use the remainder as data storage. IMO far safer than risk having everything on the system drive.

I know, I know, a reformat can't happen to me either, but sometimes I'm wrong about that.