How often does your wireless connection get dropped, if you are using Vista? If you are same as me, facing this kind of annoying problem every day, blame on Vista. It's one of those Vista-incompatible devices on your network causing this problem, the wireless router in particular.
Vista validates your network connection every time when the computer tries to connect to the network. If your router is not Vista-compatible and you are trying to connect via wireless, it most likely will not get identified the first place and won't be assigned a valid IP address as the result. In order to get work, you will need to go through the diagnose process to manually request for the IP address. Or, if you are tired of doing so, you can either look at your wireless router vendor's website to see if you are lucky to find the latest firmware that works for Vista, or end up buying a brand new one. Check to make sure it's Vista-compatible before pulling out your wallet.