The only way that I can think of fixing this is to:
1. Backup allllllll you data. Try using a utility to clone the HDD to an external drive
2. Once you are sure all of your data is saved, download Ubuntu 11.10 from their website to a flash drive
3. Extract the data using UNetBootIn.
4. Reboot and make sure your flash drive is first on the BIOS startup list (dependent on your system)
5. Once the flash drive is booting up, select Try Ubuntu
6. After this, go to GParted Partition Editor and reformat your internal hard drive (C
7. Using Ubuntu, find a program that can use the backup of step 1 to restore it to C:
8. Reboot and reset BIOS startup to HDD
Hope this helps. There may be a simpler way but this is the only way that I can think of. Hope it works and good luck!