[UPDATE: issue now fixed. If you're upgrading the iMac HD, pay particular attention to the LCD ribbon cable -- mine apparently came loose with little jostling during the drive upgrade] Hey all. I'm looking for some advice with a self-inflicted H/W problem. (Hi, Jamie!) Using HD replacement guides referenced elsewhere in the forums (http://forums.macosxhints.com/showthread.php?t=78318), I swapped out the 320GB original in my mid-2007 20" Alu iMac for a 1.5TB Barracuda. I had no obvious problems -- thought everything went fine, though the internals of my machine are somewhat different from those shown in the 2 guides -- but it was completely dead when I plugged it in and tried to start it. Opened it up again, rechecked all connections -- it started, but with horrible video artifacts (lots of snow, etc.). I powered it down and opened it up a third time, completely unplugging and reseating all connections. Although I did not originally untape or unplug the big ribbon cable at the top of the LCD panel, this time I checked this connector and pushed on it a bit to check for a tight fit. This time it booted off a CCC clone on an ext drive (I cloned back to the new int drive). BUT... I still have video artifacts -- primarily involving reds (see the pics below). For example, certain colors on the MacRumors front page that should be uniform are now banded vertically and I'm seeing horizontal lines across areas of uniform color (such as menu bars and window frames and the pictured snip from an Apple Support page). Look carefully at the snap from the iPad story; you should also see red banding in the black frame of the iPad. This may be related or not, but I'm also getting KPs at startup (no external drives attached). I upgraded from 2 to 4 GB the night before without any troubles prior to the HD swap (I restarted the machine several times immediately after the RAM upgrade to change startup drives, etc. -- no problems). I'm about to remove and reseat the RAM and see if that resolves the KP issue. [UPDATE: clean reboot after reseating the RAM. Teh snappy seems to be back.] ADDITIONAL: I also replaced the clock battery while the chassis was open. Over the last year or so, the iMac would sometimes forget speaker volume and monitor brightness settings at reboot - both going to max volume/brightness. Couldn't hurt to replace it, right? Before I open up the beast one more time, any suggestions on what I should look to fix in my botched HD upgrade?