It sounds like something corrupted your install. Since you cannot run a repair install unless you can get into Windows, I would try some things.
You might try removing the secondary display.
Boot to the Win 7 DVD and go back to the repair section-command prompt.
Type slmgr -rearm
just in case it is related to an expired evaluation period. I am not sure this command will run this way, but if not post back. I also do not know if this will mess with your activation.
Next try some of the following, although most of these should have been done during the startup repair operations.
Hit enter after each, but type: SFC /scannow
<--will take some time
then bootrec /fixmbr
then bootrec /fixboot
If normal boot still not possible, you might also try: bootrec /rebuildbcd
And I don't really think it will help, but maybe go into the bios and change the OS from Plug and Play to no. Change back later.
Have you changed the drives or drive order in the bios, if you have 2 drives?
There are some third party partitioning software you might download and burn so you can boot to one of those and check the drive and its condition. GParted and Partition Wizard
seem to be used quite a bit.