Your options are to put the old mobo back in and SysPrep Windows 7 so it can be moved to new hardware: SysPrep to move HD to another computer
Or boot to run Paragon Adaptive Restore CD on the OS to change out the drivers
Or use a backup you've saved to reimage the HD: System Image Recovery
Or run factory Recovery from its partition or Recovery Disks which came with the computer or you made off the Recovery Partition.
or clean reinstall Windows 7 with an installer for your version: Reinstalling Windows 7
You may have to do phone activation when inserting key and hope that MS gives you an exception to the mobo change which normally invalidates OEM activation.