Did you check that the SSID & channel numbers match?
Try running ipconfig /all on the laptop again, locate the wireless adapter in the list, then make a note of the IP Address, subnet mask, default gateway, DHCP server & DNS server values & let me know what they are.
LiaoGoren made a good point - have you connecting to the router using an ethernet cable? If you don't have a spare, then just nick the one off the PC for a few minutes to test it with.
Be aware though that before you disconnect the network cable from the PC, you'll have to either repeat the procedure for entering the MAC address - this time though, when you run ipconfig, you'll need to look for the Ethernet Adapter (not the wireless one), then enter the Physical Address of the ethernet adapter in to the MAC filtering section of the routers config.
Alternatively, just disable MAC filtering.
If the laptop connects OK to the router/Internet with the cable, then that means the problem is with the wireless configuration, either on the router or on the laptop.
Edited by Samm, 12 April 2007 - 07:17 PM.