Windows 7: Xbox 360 Extender Issues

Hey guys,

I've had my 360 set up as a media center extender for about a month. My media server is a Windows 7 Intel PC, bunch of disks and a TV tuner, and it just streams from that. I use it for work occasionally too (but most of the time a laptop). My extender connects via Ethernet (directly into the router) while my PC connects to the router via ethernet (routed through a dumb switch first). My router is a Linksys/Cisco WAG320N.

Until recently it was fine. I experienced some issues with my TV tuner (I pulled it out by accident, and it decided it didn't feel like plug-and-play-ing) so I figured I'd reboot. I don't remember whether this is the first time I'd rebooted since setting up the extender; but I've got a feeling it is. Anyways.. now it doesn't work. My PC can see the Xbox on the network, my Xbox can see the PC when I test the PC connection (but not when I do an MC test). I've tried allowing scvhost.exe through the FW as suggested on the (useless) "Online Help" - it basically said "make sure UPnP is enabled!" which it is. During Extender Setup on the Xbox it gives me the 8 digit code. The PC performs one step then throws an error - "Cannot Set Up Extender. Setup failed because your extender is unable to communicate with this computer" check network/fw.

I also tried connecting the Xbox and PC with the Xbox directly into the switch, with nothing else in the switch (other than internet) after a reboot of the switch, Xbox and PC; so I'm pretty sure the router can't be messing things up. At this point I'm willing to put money that Windows 7 is the culprit... only I have no idea what to try.

Any ideas? Thanks in advance!