Ah - there's another possibility. It may be that both "routers" are bagging the same DNS address - probably 192.168.0.1
Try this:
Unplug the Netgear from the Netcomm and the desktop, and plug the desktop into the LAN socket (NOT the USB one) on the Netcomm.
On the Desktop, click Start - Run, type CMD in the box, and press the enter key.
Up will pop a Command prompt.
Type IPCONFIG /REGISTERDNS <enter>
Wait for about 10 seconds, then type
IPCONFIG /ALL
You'll get a load of stuff back, among which will be something like
IP Address 192.168.0.10
Note that number.
Unplug the desktop from the Netcomm and plug it into the Netgear.
Do the same IPCONFIG /REGISTERDNS <enter>
wait...
IPCONFIG /ALL
If you get an IP Address that starts 192.168.0 anything, then the two devices are trying to use the same DNS.
What that means is that the Netcomm and the Netgear both think they are 192.168.0.1 and therefore are having a standoff.
If that's the case, the next step is to change the DNS in one of them - I'd make that the Netgear, but it's not critical which one. Once that's done, all should work fine with them daisychained.