Wireless problems with Origo router

Hi All,

Thanks to your advice the other day, I bought an Origo AWR-8210
wireless router to link 2 PC's and my PS2 to my ADSL. I've set it up
fine and it shares broadband beautifully between both PC's and the
PS2.

The problem is connecting between both PC's. I tried playing
Stronghold Crusader on both PC's and it seems to connect OK but loses
its connection after 30 seconds or so. The problem appears to be with
my downstairs PC. The router is in my bedroom and connects to the PC
up there via USB. (I've also tried using the network card connected to
the port on the router)

If I ping from the PC hardwired to the router, I can see the
downstairs PC OK although the signal drops once in a while and I get a
time out. If I try and ping from the downstairs PC that has the
wireless card in it, I can only ping the gateway and not the other PC.
(Neither the USB IP Address nor the Ethernet one respond)

Hope this makes sense. Does anyone have any suggestions as it's beyond
my network expertise? Would a wireless card in the upstairs PC help?

Many Thanks