Yes, with some upgrades. Gotta keep an eye on your power requirements - Doubt there's more than a 300w power supply in that thing, in which case even the 9800gt would be a bit too much. The best card you can get is an AMD HD 6670 without upgrading the existing PSU (Will play most games well up to 1680x1050). If you're going to replace the PSU, then you can look at higher video card options.
You may also want to check online if that motherboard supports AM3 processors. The Athlon is fine for most games 2009 and earlier, but more recent games demand more cores. Most proprietary AM2 mobos support AM3 CPUs (up to 95w) with a BIOS update. In that case, you can start looking at the 95w Phenom II X4 processors (will make a huge difference in most of this year's games).