A quick future knowledge thing is to leave your E drive alone if this ever gets fixed. Aside from copying save folders or backing up your UDATA TDATA folders, I'd never add a damn thing to it when using a softmod. Most things in the E drive shouldn't affect anything, but shit seems to happen.
Anyway, as you have another xbox that runs burned discs, get Slayers Auto Evox Installer (shouldn't be hard to find)
Unplug the EIDE cable to the error DVD drive and turn it on. With the DVD drive unplugged, you're now supposed to get error 12, but it may be error 11 like it was with my friend's xbox. Shouldn't really matter, but this is the way to unlock your hdd to affect the changes you need to it.
Turn on your working xbox as normal and run Slayers disc. When it's up, hotswap the EIDE cable from your good xbox HDD to the error 11 or 12 HDD.
On Slayers menu, go to menu option 4a and scroll down to Restore M$ Dash (5960), and let it work. Once it's done, make sure to plug your xbox hdd's EIDE cables back to their rightful places before turning the xboxes off, or they'll lock the HDD's out, and you'll be much worse off. Hopefully, you haven't done that before reading this.
If the exploit was in the C drive, it's going to be gone, but your xbox may work again and boot to the m$ dash, and you can softmod it again. Worked for me, that's about all I can say.
This post has been edited by Koitsu: Jul 1 2013, 02:43 PM