Here is the Toshiba official line on that error.
If you've already run through their fixes, you could try using the Ultimate Boot CD to test the hard drive, or run Chkdsk c: /r from the recovery console to attempt to recover any bad sectors
Then consult this link and apply the pertinent fixes to attempt to repair the MBR.
Other possibly helpful links here
I hope this information allows you to resolve this issue. If you need further assistance, please post back with a comment to this thread.
If I've managed to answer your question or solve a problem, please take just a moment to rate this post....thanks!