Cannot open files: Outllook attachments, Word, Excel, Powerpoint

Compaq Evo N800c laptop computer w/ latest BIOS
OS: Windows XP Pro with all updates current
Office 2000 with all updates current
I am running a very old corporate version of Norton Antivirus which has
never interfered with any programs; when I disable it, I still have the
problem
I am the computer administrator

I can't open attachments in Outlook(Word, Excel, Powerpoint). I get a
message that the system cannot find specified file, or sometimes I can open
the file but it won't let me save the file. The word or excel program opens
and when I click on save as, the program crashes, " Save As (Not Responding).
In some instances, I can save the file to the hard drive but still can't
open the file. If I get a jpg or mpeg file it will partially open revealing
the top portion of the picture or play the first few seconds of a video but
not all of it.

Additionally, if I open Word or Excel or PowerPoint, click on the open file
icon or click open in the file menu, I'll get the same thing, Not Responding
and the program shuts down.

I've searched all of the support fixes and can't seem to find a solution.
I've reinstalled Office2000 and that hasn't worked, nor has detect and repair.