Single client download issues: DHCP Node Type?

I have a wireless network based on a Linksys router, which hooks to a Comcast modem.
His box is a systemax mini-pc, 1GB memory. My laptop is a Fujitsu P-series, 512mb memory. My PC is homebuilt (4GB). His PC and the laptop both have Atheros based wireless chips. I mention the memory because that was our first suspect.

I am trying to diagnose why my spouse's XP Home machine is so slow downloading from the internet. He sees long pings as well. Using speedtest.net, he's averaging less than 3Mps, and has long pings. My PC, and my tiny little underpowered laptop, average about 9Mps. His proc is faster than the laptop's, and he now has more memory too. Oddly, his upload speeds are fine.

I've run speedtest on the laptop at the same location as his PC, to eliminate interference causes. His system recognizes that he's on a 54Mbps link, and he's getting a very good signal strength.

We are on channel 7, nobody else we can see is, but there are two nearby networks on channel 6. Doesn't seem to be bothering my machines though. I don't see anything untoward in the router configuration. It's set up pretty simply at the moment, I haven't fussed with any settings except setting up WEP (because there's a computer on our net that won't do WAP).

Not sure where else to look. About the only difference I see in ipconfig /all is the node types have different names - mine says mixed, his says hybrid. I do not know anything about the node types, and the effect they may have on download speeds. Or, as far as that goes, how to change them.

I'm running out of ideas. We haven't tested the network yet (not my fault!), so keep that in mind, please.

Thanks for any replies!

 

Channel 7 is much too close to channel 6, try channel 1 or 11.