Here is my setup:
HP network printer
1 desktop xp home
1 desktop xp pro/FC5
1 laptop FC5

2 routers
linksys befsx41
linksys befw11s4
routing disabled on both, I just use the befw11s4 when I occasionally need wireless for my laptop, and my media center PC (not always on)

about 2 months ago I installed vmware to check out some different distros, including FC5 (I was using FC4) at the time, and linspirer becuase there was a story about it on slashdot and I'd never experienced it.

Shortly after doing this I noticed some degraded network performance, and ran ethereal. I found my wireless router sending out tons of tcp zero window packets. All destination 0.0.0.0 with seq # 0. Like 20 a second. I never ran them since. This was done on the xp pro desktop. At the time I didn't have it set to dual boot with FC5.

Yesterday I finally got around to setting up this desktop to dual boot. Last night and today I noticed that GAIM was behaving oddly, but I thought nothing of it. I got back into windows tonight to check something and I noticed that my IMs were again working wonky in here, yet they've been fine since that day. I ran ethereal and again found the wireless router hammering out those same packets.
I did the same thing as before, powering down both routers and giving them a moment then powering them up. Ethereal is clean.

I've never had this problem before or since.

now I've had my laptop with FC5 plugged into the network for 3 or 4 weeks now without an issue.

Could some strange combination of FC5 and this particular desktop be doing something to my wireless router, which it should have no reason to even interact with?

Anyone ever experienced anything like this? Any ideas what might be going on?