If you install Windows 7 on a VM by “upgrading” rather than “clean installation,” you may load up your VM and find that Windows can’t find a driver for your network adapter. Since you can’t use the network, you can’t very well search the internet for one (from your guest OS, anyway). I had to rediscover the solution to this today, so rather than have to rediscover it a second time, I’m posting it here. (Tip of the hat to WoodyZ on this thread).
Basically you open in a text editor the .vmx file that corresponds to your VM. If you’re using VMWare Fusion for OSX, don’t forget that your Virtual Machines are, in fact, directories as opposed to single files. Once that file is open, add the following line:
ethernet0.virtualDEV = "e1000"
For style reasons I like to put it near the other lines that start with “ethernet0,” but you can put it wherever you like.