Whats with the usb key? Try getting the Windows 7 installation disk, put it in the system and boot off of it. Once its done loading, look for a repair option then find the "fix startup" or whatever its called and do that. hehe
Ok, dvd loaded, went for the repair option, loaded the system recovery options (took a minute), found my W7 OS, chose the "use recovery tools that can help fix problems starting windows", clicked on "startup repair", searched for problems, said it could not detect a problem.
3 choices now :
-view diagnostic and repair details
-view advanced options for sstem recovery and support (this one i guess)
-finish (umm i guess not...)
try the advanced tools and see if you can run "fixmbr" and "fixboot", im not certain about these tools with Windows 7 though since I haven't used it that much yet.... at least not enough to corrupt it . hehe.