Question : Problem: Correct IP address but no default gateway.

I've recently had my Thinkpad T61p re-imaged with a clean windows XP install. Prior to this I had no networking issues. Since the re-image, I've been unable to access any wifi access points. I can connect fine once I enter the passkey but it seems that there is an issue with the default gateway as I get a correct ip address (when using dhcp) but the gateway is blank.

I have tested the wifi router with other wifi devices and they work fine. I've tried repairing the ip address numerous times as well as using a static ip address where I specify the correct gateway. This also fails. I can ping the router fine at all times. I've tried this using three separate (although similarly configured) wireless access points with the same failing result.

One thing that is different on my new clean machine is that VMWare workstation 5 is installed and there are now more network adapters. I don't see how this should affect wireless adapter settings however.

Please advise on how best I can sort this out. If there is any further information you need I'll be happy to provide it.

Answer : Problem: Correct IP address but no default gateway.

check network settings for each of virtual adapters  (in control panel) and change IP address range.  As one of them is most likely in the same range as your WiFi. Had this myself. Windows is a bit confused :)
If this does not help -I would go the route -Uninstall VMWare Workstation, so it will remove all virtual adapters.