From the sounds of it, and until further clarification, he is using the computer for videos, not gaming, or folding@home. There is no need for a massive overhaul or replacement if that is the case. Please be careful about giving horrible advice without all the information present.
To Johnnyboy 1:
You can get a very cheap, low power card that will support Aero in Windows 7, if you are not interested in playing graphics intensive 3d games.
http://www.newegg.com/Product/Product.aspx?Item=N82E16814102817 - 34.99 with free shipping. Will not need a new PSU.
If you are a gamer, you can have some cheap fun with a card like this without replacing the PSU, as it is low power and gets its juice from the motherboard:
http://www.newegg.com/Product/Product.aspx?Item=N82E16814102854 - 56.99 after MIR