Major lag issues.

Sorry if any of this information is irrelevant! I just want to give you an idea of what I'm running right now so you might be able to help and the fact is I am not very smart when it comes to software/computers!

I have a Dell Latitude D600 laptop with Windows XP Service Pack 3
with:
Intel(R) Pro/Wireless LAN 2100 3A Mini PCI Adapter
1 Gig RAM
Intel(R) Pentium(R) M processor 1400MHz
Mobility Radeon 9000

I have a linksys router that 2 other computers in the house use, but it seems that even if only this computer is using the wireless it makes no difference. There are major lag and ping issues. Sometimes the game will run smoothly and other times the game will not even be able to load properly. I am really not sure what it is, because even when I plug the ethernet cord into the router it doesn't really change much. When I used a different router in a different area, it still did the same thing which makes me think it's my laptop and not the connection. I have tried reformatting and deleting stuff from my harddrive to maybe free up resources but it doesn't seem to help. Right now I'm playing on all the lowest settings and a 800 x 600 screen setting just to help it a little.

Any help is appreciated, I just wanna play Guild Wars.

PS: It happens with every single game I play, even GunBound. I really don't understand because I seem to have the minimum specs required. :/

Thanks in advance!

There are a lot of possible issues, for starters it is a lap top. Are you running it on batterys on pluged into a wall outlet? A lot of Laptops go into low power mode automaticly and have to be taken out manually every time you launch an application where performance may be needed. Other than that, have you tired GW's built in diagnostic utility?

Where is the built in diagnostic utility? Yes, the laptop is plugged into the wall outlet.