Random lag spikes

So I recently installed a new ATI Radeon HD 2400 Pro videocard on my PC so I could play GW on it. However, as soon as I started playing, I noticed systematic lag spikes (e.g. coming to a stop while running for a few seconds and being unable to use skills, then rubberbanding around a bit) about every 5 minutes or so. I don't think it's the game itself, since the problem seems evident in other programs; I used to use gmail video chat (before the new video card), and once again, about every 5 minutes, the image and audio of the other person I was talking to would freeze up. The same thing happens when I use vent, in fact, at the same time as the lag spikes in GW. I run GW on my other computer and there were no spikes aside from sever-wide spikes. The computer giving me trouble is an emachines W3650, and both computers are on a wireless network.

http://www.systemrequirementslab.com/referrer/srtest

Make sure your computer can run it. Test your system to Guild Wars Eye of The North since that is the most updated graphics for Guild Wars.

Lag would usually be internet based. Things like not being able to move but able to spin in place and rubberbanding. Or activating skills and it shows them highlighted but constantly blinking and never actually done.

Freezing would usually be a hardware issue. Such as not enough RAM or other hardware issue. Freezing is when Guild Wars completely stop responding. Nothing is moving, and trying to do something but nothing is done. Like you would be stuck in place, but not be able to spin around in circles. And clicking skills or hitting buttons wouldn't even show anything highlighted. Things like that are usually not an internet based issue, but hardware.

HD2400 is enough for GW, but how much Ram do you have and what kind op CPU.
you can use the free program CPU-Z to find out about that if you dont know it.

To clear up on terminology, it does not freeze by your standards, but does lag in a similar way (able to spin in place, skills light up but don't actually execute). I think because my other computer can run GW with no problems and they're both on the same router, that it's a problem with this computer itself, especially since other applications have similar problems.

And I did test it on that site, and it says my computer passes and is in the recommended range.

According to CPU-Z, I have an Intel Celeron 440. I'm not exactly sure where to find RAM in CPU-Z, but under memory it says:
Type: DDR2
Size: 1024 MBytes
Channels #: Single

Meaning you have 1GB of DDR2 RAM in 1 slot

means your PC can run GW

Does your GPU comes with a program that makes it run in 2D/3D optimisation? Disable it if it does have that option as some of the latest GPUs will attempt to run in low power mode even though you're running a game.

I'm guessing it's your wireless adapter then. Maybe not strong enough signal for one. Probably why one works and the other doesn't.