Hello everyone, I have a late 2009 21.5 iMac which had a graphics problem (vertical stripes and later black screen) and eventually I had the graphics chip replaced. It worked for around a month then upon booting the screen shows the apple boot and right before login it goes black again. I tried resetting both Smc and NvRam but nothing. After a couple of visits to the technician I was told that unfortunately the whole graphics card is damaged and it has to be replaced. I looked around online and the cost is simply insane. Now, the weird thing is that when connected to an external monitor the iMac works fine. No chopping graphics I even play games. While connected, the display settings, shows only the external monitor and no other choice. Even more strangely, on occasion but very rarely , after a reboot , BOTH (imac's and external) monitor light up and the external works as an extension desktop . Keep in mind that at the time of the gpu repair I removed the cd drive and had an ssd and a second hard drive installed. Please help!!