You need to have sp1 for xp installed to see above 137 GB on drives.
The actual size of the drive and the formatted size will be different. Formatted will be lower.
Drive manufactures use 1 gb = 1,000,000,000 when its actually more like 1,024,000,000 per = 1gb something like that. cant rememver actual numbers.
I have 2 250 GB drives in a raid 0, Formatted size is only 465 GB instead of 500 GB.
You might also check to see if there is a bios upgrade for your mobo. There is also a jumper on the drive that will limit the capacity, don't remember but 130Gb sounds right. Just two more suggestions, the others were correct as well. It sucks but the bigger the drive is the 'more you lose'. My 200Gb drive is only 183 formatted.