You could _try_ to put the drive as-is into the new machine, boot off the Win7 installation DVD, and do a repair install. This will search for drivers that match the current hardware. Three notes:
1) Clone the drive first so that, in case of damage, you still have your data.
2) You will probably have to phone Microsoft to re-activate the copy of the OS. They've been decent about it with me.
3) If it works, immediately go to the Microsoft Update site and see what updates are needed for the drivers that you just installed. I don't know whether you will or not, but you may need to re-install the Intel Matrix Storage Drivers.