VFBACKUP and VFD.VXD Error

A 486/win95 machine, external modem and parallel zip drive attached, became sluggish after installation of McAfee’s Uninstaller software. Now, this error is displayed during system startup:

VFBACKUP could not load vfd.vxd Run Windows Setup

The computer must be powered off at this point to restart; can only start at command prompt from Win95 Menu (option 6)

Running setup has not resolved the problem, neither have the resolutions proposed by Microsoft (extracting vfd.vxd from the cab file to windows\system directory, editing msdos.sys or config.sys). Any other ideas much appreciated!!
Thanks
Sandy