make sure that you're network key is correct and under "preferred network" you have to edit your profile and restart your computer now if it wont work try to check for the "advance wireless settings" of the router and change the ff:
Beacon Interval = 50
RTS Threshold = 2304
Fragmentation Threshold = 2304
Now if this wont work i believe you have to upgrade the fw of the router..
just to isolate the problem try to use other computer and see if the others can connect
mmmm so if you done the advance wireless settings and you upgraded the firmware of the router and its still hangs on "acquiring network" try this one more thing on the "wireless zero configuration" screen click on "change the order of the preferred network" then under preferred network delete/remove everything that you can read... then try to connect again..