unable to boot to 2nd internal drive after drive letter relabel

[rag2mop]

I have Vista Home Premium with two 320 GB internal hard drives (C) & (E). I am trying to put Vista on drive E and upgrade to Windows 7 on drive C.
I had successfully cloned the drive C of Vista onto an external hard drive and copied it to drive E (the second internal hard drive). When I copied the cloned copy of Vista to drive E, the system changed the drive letter to L. Everything was working fine and I could boot into either C or L.
In a fit of neatness I guess, I decided that I would like to have the newly labeled drive L designated as drive E again and changed it to drive E in "Disk Management" while I was booted into drive C.
Now I am unable to boot into the second internal drive. I just get a blank screen. I can get "Task Manager" but nothing else, not even the "Start" icon.
I booted back into C and changed the drive back to L, but that didn't work either.
I tried to boot the second internal drive in Safe Mode, but just got a blank screen, without the start icon.
I tried restoring to a previous date, but that wouldn't work and it only restores C anyway.
When I'm booted in drive C, it shows the second internal drive L and shows all the files and programs that should be on drive L.
How do I get the drive restored so I can boot into it?
Thanks to anyone that can help.