If you feel like you could spare some time on the project and you have an extra hard disk, I'd suggest the following:
First make a clone of your HDD. In case something goes wrong you'd still have your valuable data safe. There's free cloning software available in the net, like
Clonezilla.
Gyrene's suggestion of connecting the disk as an external drive for copying data into a safe place is also very good. An external exclosure will do the job, but I prefer dedicated Sata/IDE to USB adapters for their versatility for one time jobs.
After you've saved your data, you can safely look what happens with a new motherboard. With luck, you'd only be asked to reauthenticate Windows. Win7 doesn't have the repair install option, but similar results are acquired by making an
upgrade install over the existing one. Just make sure that you either have or don't have ServicePack 1 on both your installation disk and HDD.
If your Windows accepts the new components with ease, your next task is to get rid of the old motherboard drivers. My trick to do this is
this nice little batch file, plenty of advice on the subject in that thread. Remember to run the batch as an administrator.