You might try removing the CMOS battery for a minute or two and then replacing it.
The motherboard should work, but you'll likely have to reinstall and reactivate the OS. (I suggest you download a Windows 7 ISO from Digital River and burn it to DVD for this purpose.) Also, if it doesn't have a removable IO shield, you'll have to cut out the opening yourself.
The Windows OEM license allows you to replace the motherboard for reasons of repair; if you have trouble activating, call Microsoft's 1-800 number and explain the situation.