I've just installed an SSD into my 2011 21" iMac and thought everything had gone fine, but when I turned it on the display did not come on, even though it sounds like everything is working, including a fan which is now on full power. I've had a look and it doesn't look like I have been able to install the internal displayport cable back to the way it was, which connects the logic board to the LCD. I've done a bit of searching and it seems others have written that this particular piece is rather vulnerable when installing SSD's. I have attached a picture of the logic board end of the cable as I can't tell if the end of the cable (which is silver and bent at 90 degrees) is part of the original cable or something which has come away from the logic board. I know that I can purchase another cable, but if the problem is something which has come away from the logic board then another cable isn't going to solve the problem. Someone please tell me I can get myself out of this rather sticky situation!! If anyone can help that would be great!