Thomson 585n modem connection to another computer

Just gone on to LLU set my 585n modem up no problems. However I have another computer and I can not get it connected to the modem. Its using a speedtouch 121g wireless connection and I put all the info in key etc and scan and it does not show the modem to connect.
I have enabled accept new connection in the modem.
So what am I doing wrong? help please

the 585 is new then ?

Check the wireless is enabled, ie is the light on, not always on "out of the box".
Is the 121g close to the router when trying this ?
Can you put 585 into b/g only mode in case that is causing problem with non-N 121g.

Yes the 585n is new. The wirless light is always on and the laptop connects ok
But is the computer upstairs that can not see the modem.
What is b/g mode?

wireless standards include 802.11b 802.11g 802.11n there should be backwards compatibility but if an 11n router is not connecting I would set it to 802.11g in the user interface and try that.

Also you should either move the upstairs computer to the router or vice versa temporarily or try the 121g dongle in the laptop to see if you can figure out what the problem is.