Recently I've been experiencing this problem whenever I turn on the computer. The screen becomes distorted (i.e. random lines in random colors appearing in random location on the screen) for 1 to 2 seconds before proceeding to the normal POST screen.
I wonder if it's a sign of the display card failing. But the computer still functions normally even when playing games for prolonged period. This is a custom built desktop computer, display card is a Sapphire HD7850.
Any ideas?
Do you have onboard graphics? Try removing your graphics card, then boot your PC using your onboard video.
If you no longer see graphical artifacts, then you can be quite sure that it's a GPU issue.
Usually when a GPU shows signs of corruption that's a possibility that the VRAM memory chips are failling.