Win2k pro SP2. Running more than 1 year fine until last night. IE 6.0 stops showing the window. The process table shows IEXPLORER.EXE running. Click "My Computer", window shows up but nothing in the window, then "not responding" error popup shows. The machine boots normally and everything else seems normal but all Windows applications can not run properly. Any suggestions? Thanks.

Try reinstalling IE 6.0 or try reinstalling 5.5 SP2. Windows will not run without IE. You could have a virus. I am not sure if you can reinstall in safe mode or not, but it may be worth a shot.
Worst case scenario is you reinstall Windows 2000, but do not format the drive. It may just overwrite the current WINNT directory, and of course all program will be there, but need to be reinstalled due to the new registry. This is why it is good practice to use partitions. I am not sure if Windows will wipe the partition or just over write the WINNT dir. I know you could have successful recovery with NT 4 and 98 with all other data remaining.

Thanks for the info. I will give it a try tonight.

Problem resolved in an odd way. This PC was trying to use another local PC as DNS server (don't know why) and that created all the mentioned problems. Reconfigured IP and everything is fine now. I was thinking about applying SP3 but based on some of the posts here, I'd rather wait a little longer.