File, Open lockup Office Aps and Windows

Ok, Here’s the scenario:
Win98SE with Office 2000 SP3, McAfee 4.5 SP1 VirusScan, IE 6 SP1, Media PLayer 9, IBM Client Access all with latest service packs and patches:

User in Excel, goes to File, Open, and gets lockup when trying to explore here files. Windows Explorer is also tanked. Seems to happen only with Excel, and only in the morning hours (Not sure about this). Again, all software patched and packed; Office 2000 Re-installed (over top existing system) and checked out more obvious issues (network shares, OK; Files in use, NO; etc…)

Any help would be greatly appreciated. Also, Explorer.exe is the same, no change in size or date as opposed to a working machine.

Thanks,

Leo