The MBR has failed to copy or the drive letter has slipped.
Determine what assigned drive letter is now by booting DVD Repair console, click through to Recovery Tools list to open a Command line, type:
SELECT DISK 0 (confirm this is WIn7 HD # from list)
SELECT PARTITION 1 (confirm this is WIn7 part # from list)
Is the drive letter listed correctly?
Is it System partition and marked Active? If not, do you have the 100mb System Reserved partition in the partition list. Detail it and confirm it is System and marked Active and note any drive letter.
If there is no 100mb SysReserved partition and Win7 partition has correct drive letter and is not marked Active, type ACTIVE next, then EXIT and return to Recovery Tools list to run Startup Repair up to 3 separate times with reboots to write the MBR to Win7.
If the drive letter is missing or has changed, use free Paragon Restore CD to fix it: Moving Win7 Partition to Another Drive
If Startup Repair will not work because an installation is not showing to repair, try to force it's discovery by manually running these commands which are automated in Startup Repair:
bootsect /nt60 C:/ (if System partition is C)
If necessary then run Startup Repair up to 3 separate times with reboots
as it runs multiple tests and attempts to repair before rewriting the MBR.