What did you use to create the partition? There used to be programs like partition magic that would partition a drive without losing any of the data, haven't used a program like that is years.
Just guessing here but if you put the windows disk in and run the setup program there is an option to repair a installation. I've never used that option but it might repair the bootloader?
Edit: Seems Windows 7 has a built in partition resizer, didn't know that.
http://www.howtogeek.com/howto/windo...windows-vista/
Is that what you used?