A real puzzler

Hi. I've had a problem running GW for a while now. I've submitted tech questions to the main site with no response, so I thought I'd ask what you guys think.
Whenever I play I always get stuck on the decompression part. You know, right when you portal to a new area the loading screen appears. It says connecting first, which takes way longer than it used to, then it downloads some stuff, then it says decompressing.
Now this is where it gets good. If I leave the game in fullscreen it can take hours ( )to decompress this stuff. During this time there is almost no hard drive activity. As far as I can tell my computer isn't doing anything. But if I put it in windowed mode it loads right up, usually to 100% before the window can even form.
So my question is: what the hell is going on? I used to play GW on this machine when it first came out without any of these problems. Then they did that patch to create the battle islands and it's been crappy since. I haven't changed any hardware and I've tried reinstalling both GW (from the CDs and the online client) and Windows XP.
Any insights would be gratefully recieved.

delete gw.dat - re-install the game to a NEW location, and start from scratch... see if that makes a difference..

If that makes no difference, try defragging your computer, it maybe that it has to place pieces of the files all over the place on your hard drive...

Thanks for your reply. I've tried that, even reinstalled onto a completely different drive. Both drives are nice and defraged.
Any other ideas?

Anyone? Someone out there has to have something I can try. Please help!

so it slowly but eventually decompresses, but its instant if u switch to window mode?

I used to experience significant lag on the loading. Now I did a sort of shotgun repair on it though so I can't tell you which of these options actually fixed the issue. I ended up upgrading my memory and my graphics card to a higher memory card, 128 to 256, and I no longer experience this loading lag. Maybe this will put you on the right track. Personally I'd try the mmeory upgrade first. Maybe I'm not remembering my Comp 101 class correctly but all active programs are shifted to RAM as they run. Maybe your available RAM is taken up with other processes and the computer has to do some shuffling to get all the new stuff in there. I don't know why windowed mode would make a difference though if this is the case. At any rate this is what fixed a similar issue for me maybe it will work on your problem.

Well before you go off buying new ram you might want to do a ram diagnostic to see if its actually ur ram thats screwed. Use the tool below.

http://www.memtest86.com/

Always nice to have someone who knows where to find the necessary utilities. Although for me it wasn't so much screwed RAM as a general lack of it. Then again it could just as easily have been screwed up RAM that wasn't functioning properly and therefore making me have much less than I thought I had. I'll have to try that utility out.

Thanks for the advice. I appreciate it.
I have 1GB of RAM and the Task manager shows me only using about half of it while running GW. I checked it with the program you suggested and it came back fine. My cpu is an AthlonXP 3000+ and my vid card is an X800 XT with 256 onboard.
The thing is I used to play on this system without anyproblems. I have zonealarm, but turning it off doesn't help. And it decompresses much faster in windowed mode than in fullscreen.
I have a dinky Compaq I use for homework and runs GW fine, other than having cruddy graphics.
I'm going to try a couple of other things. Maybe reinstalling my mobo drivers will help. Thanks again.