Licensing dictates an OEM version is for a licensed for a specific hardware build. Reatail versions allow for moving from one platform to another.
At any rate, if you're running Windows 7, it should work fine, but be prepared to spend another $90 if it doesn't.
Make sure you download the latest BIOS and drivers for the new board from the manufacturer's web site and put them on a memory stick, DVD, or CD. Uninstall the old video drivers or if you're out of date, just get the new drivers. Put the Nvidia drivers on this disk/stick as well.
When starting up with the new board, make sure the new board's disk controllers are set to the same disk mode (ie AHCI) as the old board and the drives are attached to the various corresponding SATA ports.
The first start up with the new motherboard will result in the old chipset drivers being removed. Then you'll get a notice of Windows needing to restart for the new hardware configuration. Upon restarting, you'll have generic video drivers and other drivers. Update the BIOS according to the new board's manufacturer's instructions and make sure the disk mode is the same on as above after the BIOS update.
Install the new chipset, USB, Audio, and LAN drivers and reboot for each when prompted. Finally, install the video drivers.
Just curious though, what are your temps on those video cards? They run pretty hot as 97C is the max temp. I'd only worry if either card is approaching that temp.