Bootcamp vanished?

Hi everyone,

I have a MacbookPro from I think late 2009 (can't remember when I bought it).
I recently did a full reinstall because it was clogged up with useless crap I didn't need.
Seeing as I did a full reinstall I thought I'd do a bootcamp and install windows XP on the partition.
It's been fine and I've booted into a few times, however I've literally just gone to boot into it and it wouldn't boot to the desktop. It did the initial loading progress bar, but then just went to black screen. So I rebooted into Windows Safe Mode and everything was still there. I tried once more to boot back into Windows XP, but again black screen so I just booted into OS X. I looked in Finder and now the BOOTCAMP HDD partition is no longer there? I then looked at boot camp assistant and it has no acknowledgement of the partition, and says I have the full 320GB HDD. However, that's not acknowledged by Finder, as the Windows partition had about 50GB or so on it.

As I'm still relatively new to Macs, I don't know where to start now getting the partition restored/wiped so ANY help at all will be appreciated. (Google didn't give me any decent answers)
If any extra info is needed, feel free to ask and I'll get it ASAP.
Thanks

Ok I've managed to rediscover the partition. For some reason the drive wasn't mounting which I found out by looking at Disk Utility. I've remounted the disk via that and I can see the drive and its contents.
It still however boots to a black screen.
Should I see if I can do a repairs with the Windows disk?

It sounds like the Windows video driver has become corrupt or something changed it (perhaps a program or update). What I suggest is boot into XP in safe mode (since that's working) and remove the video driver.

You can do that by opening Control Panel, System, Hardware. Open the hardware tree, right click on the video driver, select properties, and remove it. Now see if you can boot back into XP normally. If you can, insert your Leopard or Snow Leopard DVD and allow it to install drivers again.

If that doesn't work, you can try repairing Windows XP with your disk.