When you ran CASH, did you select restore Xbox to original and mod with Krazie's?
It is very important that we get the mod fixed first. No matter what you do to get XBMC running, if you have a problem now you will have problems in the future.
If you have done that with CASH and still have problems I would use Slayer's to restore the drive to original. CASH may have the option to restore to original, but it has been a long time since I have used it. Put Krazie's on there and redo the softmod. Use Xbpartitioner first to format the F and G drives with 32k clusters then worry about getting XBMC on there. Get one thing fixed at a time.
Before you do anything else, make sure your eeprom is backed up and you have it on the PC. If all else fails you can make a Xboxhdm disk with the stock C files and rebuild the HD with it and lock it. Then you can re-mod the Xbox. You should have one of these disks if you managed to get a new HD in the soft modded Xbox.