Hi,
I was having a problem with vmware and stumbled upon a solution. I was using these forums as I tried to troubleshoot, so I thought I'd share in case someone else comes across a similar problem.
Problem: vm can't connect to internet. Host is windows 7, vm is windows xp. Both had avg 2011 free antivirus, and used windows firewall. The vm could ping (ie. I tried pinging www.google.com and it was responding). Also, it said that it was connected. I tried the whole "change to NAT" or "change to bridge" thing. On the host I tried disabling the firewall, antivirus, I even uninstalled avg, tried it again, then installed avast, then tried it again, but no dice. I did the same thing with the vm but no dice.
Solution: "when in doubt, pull the plug and put it back in", which is essentially what I did. I double clicked the network adapter icon. Then where it says "connected", I unclick it. The VM acted as if I had pull the ethernet cable out of t he computer. Then I clicked the checkbox so that "connected" was checked again. Magically I could go on the internet with the vm.
I don't know why it worked, but it did. I spent a few hours troubleshooting this problem. I don't even know if I'm going to use the vm for now, but I just wanted to make it work for the sake of making it work.