Maybe leave memtest running all night long? Give your RAM a couple of weeks worth of activity overnight?
Will do.
Btw, I've ran sfc/scannow several times after encountering problems and each time get the same result: It finds errors but is unable to fix them. Would this be linked to faulty ram?
It could point to a dodgy disk, which might also be the cause of your problems. Most manufacturers have their own disk checking utilities that you can grab from their website. Have a look for one.
I have used crystaldiskmark before and dont remember seeing any errors on there - cant remember exactly if it actually tests for any mind you 

Does anyone know of a program like memtest i can use to test my ssd?That sucks, can you get it replaced?
I'd be getting the data off it pretty sharpish.
How old was it out of interest?