Apparently I loaded up my copy of 3DS Max 8 this morning and some preference option must have been changed(maybe a shortcut key?). Whenever I zoom, rotate, or pan, the models in the viewport are not rendered and only their bounding box appears. It's very frustrating to work on a model like this, so if anyone could help, thanks :)

I havent used max for a good few years so this might not help ;-)

can you right click in the view and change any settings from box to wireframe/textured etc? Theres a menu up top called "views" maybe theres some options in there to set the viewports to the correct viewing method?

in customise, revert to defalut layout - it seems like youve got adaptive degradation on.

Adaptive Degradation is not on.

Well, this does sound a lot like Adaptive Degradation to me :)

And in order to turn it off, just press "o" from your keyboard to toggle the setting, you probably pressed it accidentally in the first place.
"Revert to default layout" will not fix this