It may not happen with anything else, as nothing else may push your system as hard as Morrowind does.
Try: Right-click My Computer, select Properties, select Hardware, select Device Manager. Scroll down to
Universal Serial Bus Controllers, open the plus sign next to Universal Serial Bus Controllers, scroll down the list to USB Root Hub and highlight. Right-click that entry and choose Properties. A window will open with four tabs. Choose Power Management. The page should say USB Root Hub and below that, should be a box ticked for "Allow the computer to turn off the device to save power" Untick that box and close. Close all dialog boxes, including Device Manager.
The other thing you can try is uninstalling the mouse driver...that'll often fix things.