Hi guys, Just switched off my electricity at the master switch to replace a socket (nothing to do with the iMac). I turn this back on and boot my iMac, to find that it had a stain-like pattern on the left side of the display, and the CD drive sounded muted (as if something was going wrong with it). However, both of these have gradually gone over the course of a few minutes. Not normal behaviour, but is this something that I should be really concerned about? Many thanks!