Have you read http://support.microsoft.com/default.aspx?scid=kb;en-us;Q297185 and tried the chkdsk noted?
After downloading and using TurboTax, I now receive the blue screen of death. I can not even get into safe mode. The error message reads "unmountable_boot_volume". The help desk said that the hard drive is gone since the diagnostics test failed. Is there any other options?