Not able to boot Ubuntu Karmic Koala

Not able to boot Ubuntu Karmic Koala

I took the ISO image of Ubuntu 9.10 release candidate and did a CD burn. I installed it on a WinXP Home system (Wubi). For the first two weeks both the OSs were working fine. But now the Ubuntu boot is not working. I don't know how to fix it up. Any help will be highly appreciated.