Western Digital (WD2500JB) Caviar SE Hard Drive

Can Someone help me please. I recently purchased a Western digital 250GB Hard Drive which I installed in my Desktop PC. The BIOS detects it as 250 GB but when I try to install Windows XP it only comes up as 139.9 GB, I Fdisk the drive and selected large drive but it came out even worst, the bios and windows now only recognise it as 33 GB and I can`t seem to change it, I`ve tried with different Softwares , patches and programs but it remains 33GB. I need a solution please HEEELP!!!