If Windows 2003 use Remote Desktop, and then you can use the services.msc, or the MMC to view what is going on.
If Windows 2k, the safer thing to do would be to use Terminal Services, or some of the freeware Monitors suggested earlier.
If it stops responding, there is an issue. If the server drops there is obviously no information you can obtain, other than it is no longer online.
On a higher level you could use the Microsoft Systems Management Server to monitor and control all of these events, but I was assuming your were a relatively small site.