Your specs are very old. It would probably do better to buy an up-to-date machine, because if you want to play anything 3D these days, you will certainly fall on the short side of any game\'s \"minimum requirements\".
The graphics card and RAM are the most important. Get 512mb+ RAM and any card of 64mb+ and I think you\'d have no problems with PS (that is unless you got a Radeon... PS doesn\'t like them very much).
As for the \"server not found\" issue, ensure that you have the correct server address (planeshift.fragnetics.com, or try the server\'s IP: 203.81.47.74) and that no firewall or router is blocking UDP traffic through port 13331.
Also make sure you\'re running OpenGL mode and all your drivers are bang up to date. If you still have trouble, try Safe (slow) mode, but it will rely alot heavier on available RAM... which, let\'s face it, you hardly have enough of as it is.

Hope this helps
