Unable to connect to Senao AP NI3-2511CD-PLUS3 & Netgear NIC

I have one Senao AP,one Netgear Wireless NIC, A aDSL router and two PC.

What I need is to connect the both PC to internet but the PCs are in different rooms in house so I thought to use wireless networking.

So made Senao to work in AP mode, installed ethernet NIC on one of the PC, (the other PC is near aDSL router so no need to connect that to wireless AP.)

In the client PC I am able to see the AP and its having around 60% signal strength but I am not able connect to AP.
I tried to enable filtering and specified MAC of the NIC in AP but still no success ie . network is visible is PC but unable to connect, even with filtering disable, I can't connect.
BTW, this client PC is having WindowsXP.

Can anyone suggest me that where I am wrong when I have 60% signals but still not able connect.