Very Broken MacBook (file system errors, won't boot)

Hi all!

I'm normally very good to my computer, but lately it seems to be on the fritz in a big way. I've looked for others with similar problems and havent found anything. I think it might be a compounding of issues.

I have a mid-2007 black Macbook, running Snow Leopard and boot camped with Windows XP.

It won't boot SL. I press the power button, it turns on, the grey apple and the wheel show up....with a grey progress bar. The progress bar VERY SLOWLY (takes about 5 minutes) gets moving, and then suddenly disappears. The grey apple and the wheel stay. I've let it sit like this for 20 minutes with no progress.

I tried a RAM reset. No change. I tried booting in safe mode, it just reboots itself. I can boot to my Leopard OS disks (Not SL, I can't find them) and run Disk Utility...but...

It fails on both repairs and verifys. The actual red errors change every time, but it always says "Incorrect block count for file MobileDevice." I recently did an update for my iPhone, with an update for iTunes. It started behaving sort of strangely and slowly after that. Eventually it crashed and I had to hard reset and this whole mess began.

I would simply reinstall leopard, but for some reason my mac drive won't mount. The only option I have for an install is on my windows partition.

I have read recommendations for fsck, but I can't boot in single-user mode, and typing it into the CD booted terminal seems to do nothing.

So, a lot of problems here on a relatively old machine. Any ideas?