I have a annoying fault with my ASUS K70IJ laptop. The problem was present when I bought the PC, so I sent it back under warranty, but it was returned with the message "no fault found", and indeed when it came back, the
problem had disappeared. That was the way it stayed for the next 30 months, but now the problem has reappeared.
It's a problem with the graphics hardware, which manifests as soon as the PC is powered up (i.e. before even the BIOS has started up). The problem is that the red colour plane of every pixel on the left half of the screen for which the demanded level is 64 (out of 255) or less turns full on. If the demanded level is 65, only every other horizontal line is affected (I can't tell if it is odd or even lines). At 66, only the line down the centre of the screen is affected. At higher levels, there are two or three lines down the left side of the screen which seem to limit at this level (which has the effect of making them look cyan when they should be white).
It may be that the fault is simply a bad connection since it seems to be intermittent, but even so tracing it will be difficult. I've not seen any mention of a fault like this on any third party fora.
Finally, for some reason, ASUS have no forum of their own for laptops (or notebooks), although they seem to have fora for all their other products.