About 2 days ago I got a boot error from Vista saying that volmgrx.sys was corrupt or missing,with error code 0xc00000e9. I did a repair and although it didn't fix the problem, I was able to hit enter and Windows would boot normally.

This has suddenly also stopped working when I turned on this evening - whenever Vista boots I get the same error. Safe mode won't fix it, last known good won't fix it and even putting in my Windows CD and doing a repair won't fix it, even though the repair log says it found that the file was corrupt and supposedly fixed it. Same error happens as soon as I reboot after the repair.

Any ideas?

Did you try restore to "Last known good configuration"?