Resolved Drive size issue with XP

Just a quick history first. My brother-in-law's Dell Dimension E521 caught a virus. IE was "high jacked" and the machine had no internet access, just a message that read, "a virus has been detected, click this link to buy our virus cleaning software ". Of course, when you click the link, you get directed to a scamming site that wants you credit card information.
Since this machine is used exclusively for face book, don't ask, and holds no valuable data, I decided to install a XP.
During setup the drive is being recognized as a 131 GB when in fact the drive is actually 250 GB. Any idea what is causing this issue?
I have my thoughts, but will hold them to myself for now.
Thank you

 

I knew it. I was forced to use my original XP CD due in fact my XP with slipstream SP2 is giving me fits.
Thank you so much.