Actually, in addition to this, I have managed to log in - as after the system restore, it would show the normal start up display, and go blank but was still on - and my log in screen briefly flickered. I managed to use the webcam to recognise my face to bring up the display and log in normally.

Following this, I have now plugged in my HDMI cable to my TV, which now shows my display on the tv screen, but not on my laptop (Normally it will show both as my settings) so does this suggest something wrong with the display on my laptop??

These symptoms point towards a Video Card problem. Try these steps:

• Do a clean installation of the video driver as explained here. Go to the Support website a make sure you have the latest BIOS version. 
• Run an ePSA test. Check if there are any signs of distortion or flickering during the test.
• Use the FN+F7 command to turn the discrete graphics off and run only on the integrated video card. Check if the issue persists.

Let me know how it goes!

Hi Naomi, thanks for your reply! 

I did the last test, pressing Fn+F7 and changed the graphics card and rebooted. Following this the laptop display has stayed blank (though appears to be backlit) 

Now following this it no longer shows on my tv as the secondary monitor. Does this indicate it is indeed a graphics card problem? And how do I go about getting this fixed?

Also, do you know how to get it back to how it was originally so I can at least have it display on my tv as a secondary monitor so I can still use my laptop in the meantime? 

Many thanks

FN+F7 disables the discrete graphics and leaves only the integrated graphics, that's why there's no display on the external monitor. Do the test without the external monitor and check for distortion.

To enable the discrete video card back, you simply need to use the command again and restart.

Hi again, 

i have attempted to do the ePSA test but I'm not sure if its happening correctly - I have watched the video and read the support page, I was able to get to the first initial menu (which is flickering and is distorted) and click 'Diagnostics' 

Following this, it will flash between block colours of red, green, white and black, and beeping. Following this, the screen goes blank, followed by three sets of three beeps, and a short melody, and keeps doing this, but I not shown anything on screen, no error codes or menus to go through. 

Are these symptoms of something or am I missing something? Many thanks for your replies, but this is a very frustrating issue, and has only occurred not long after my warranty has expired so I can't even engage in technical support chat so this is my only option.