WORD 2000 causes comuter to freeze

When I run Word 2000 on Windows ME, the computer either sends me an error message as it freezes or gets stuck in hourglass mode when I try to open more than one document (and sometimes when I even try to open just one document).

Here are two recurring error messages:

"System is dangerously low in resources!"

"EXPLORER caused a general protection fault in module USER.EXE"

I recently had virus trouble with my computer. Norton 2005 is now installed and has scanned and cleaned the disk. I tried reinstalling MS Office 2000 but the problem persists. I ran a thorough scandisk. What else can I do?