Lag constant

Okay I just came back to gw and I just reinstalled it
AMD sepron processor 3800+
1gb RAM
NVIDIA Geforce 6150se nforce 430 graphics card

But my fps is like 1-10 all the time, but when I used to play it was fine
and lag was the reason I stopped

This has been an on-going problem since I first started playing GW. The lag, bad ping rate, "rubber-banding" and other nuisances are very annoying! This also makes it downright difficult when playing a character where skill timing is critical (i.e. permasin), and can result in a loss or defeat! Despite the scheduled "server maintanance", I've yet to see any improvement.

trying to play on that GPU is causing your low low low FPS, not anything you can do about it, other than upgrading.

Lag is caused by many factors, often they are PC side and NOT server side. Blame your ISP, connection type, distance to server, router, computer itself, viruses etc... first since they are more often the problem than Anet is.