I am updating a friend of mine's old Dell Dimension 2350 and after installing Windows 7 Pro on it the display was very large and I couldn't adjust the resolution but after a lot of google-ing and trying different things I finally found the solution that worked. A lot of people advised that I download the video driver from Dell and run it in XP Compatibility Mode but that never worked. So what I did was download the driver for the 845GL chipset from Intel. After installing it go to the folder where it is located and right click then properties then compatibility then make sure you click the box to run as administrator then click change for all users and when the next window appears make sure all the same stuff is checked and then click apply. After doing all that back out and right click on the driver program and click compatibility to make sure all the check boxes you just checked are still checked then run the program by double clicking and follow all the instructions for the install. When it asks, restart your computer and the video resolution should be fine and adjustable!

I don't mean for this to sound elementary but I wish I could have found a detailed explanation on how to do it before I wasted so much time. The link to Intel's site for the driver download is below.