referenced memory error

I am running Windows 2000 workstation. I am on a Windows 2000 server network. I have installed any new software on my PC. I am typing in Excel, currently. Above are the facts. Here is my question. What would cause this error?

The instruction at “0x301faae8” referenced memory at “0x0079f00”. The memory could not be “read”.

Can anyone help? Thanks!