limited virtual memory

I fcing this problem in win2k advserver when I press ctrl+alt+del to put my user name and password an error pop up telling that I have limited in vitual memory when I press ok it show me again the logon screen.
it’s happen again and again ..etc. with any chance to go inside the system even by safe mode to correct htis probelem.
I increase the ram and nothing change , the proble still presist.