Intel does not support the 865 for Windows 7. These older graphics use XPDM drivers and Window 7 likes WDDM 1.1 drivers. You may have luck trying a few diffent things.
I got Widows 7 working on an old Dell 855 based laptop. Was a pain as i had to install Vista (so you need access to Vista install DVD), then used a driver utility called DriverMax (google it) and extracted the display drivers. Installed Windows 7, then put DriverMax on that install and restored the display drivers.
Heres a link:http://www.win7heads.com/hardware/10101-intel-855gm-driver-install-dell-inspiron-700m-windows-7-a.html
I also read someplace you can "Add Legacy Hardware" feature in Windows 7 and pick the Intel 965GM - which might get you 1280X800.
If this is a desktop... can you an a graphics card? But once you start putting $'s into this you might as well get new or newer mainboard.