M17x R4, graphics card problem

That is a very strange card to be in your laptop as they were never released with the 640M. 

What is shown in Device Manager under Display Adapters? If it says Microsoft Basic Display Adapter or Standard VGA Adapter then all you need is a modded driver. It can be a little tricky if you've never done it before but it isn't too hard.

It is a very low end GPU though so you'd be better off trying to find a decently priced 680M which will be plug and play or even go for something newer like a 970M or 980M (these need modded drivers though)

well it used to show the 640m as a 640m but with some sort of windows error i forgot but one day it just disappeared and only the integrated graphics were showing up in the device manager

If the card has gone completely from Device Manager then it could be dead or may need to be reseated. Occasionally a Windows update will cause the card to disappear so you could try restoring back to a point when you know the card was working or you could try reinstalling Windows. 

but how could it just suddenly die while not actually being used, as far as i know i was running solely on integrated graphics and does showing up in the device manager have something to do with whether i have the correct drivers or not?

A GPU without a driver installed will show in Device Manager as a Microsoft Basic Display Adapter or Standard VGA Adapter (depending on what GPU it is). If it isn't in Device Manager at all then Windows doesn't know it's installed. If the BIOS doesn't detect it either then it's not a Windows issue. 

I would try removing the card, giving the pins a gentle clean and reseating it.