I have a HP Pavilion AMD Athlon Processor 550, Model 8662-C. It had 128 MB RAM. I added another 128. While putting the memory in I disconnected the processor fan. When I rebooted the machine it went through the starting post and said that the fan was disconnected and see a technician immediately. I immediately turned it off and plugged the fan back in. Then when I rebooted the blue HP screen comes up. The yellow light is on and it stays on a long time, and then it goes to a blank screen with a blinking cursor in the top left corner. If I press escape while the blue screen is on, it will take me to a screen that tells the type BIOS, then it goes through and checks the memory and it all passes, BIOS and video is shadowed. Then UMB upper limit segment address E966. Then it recognizes the fixed disk the CD writer and the dvd player. Press F 1 to enter setup. If you don't press F 1 it brings up a boot menu. Enter to select a boot device, choices are removable drive, hard disk, CD, or network. Enter to accept or exit. No matter which one you enter it takes you to the black screen with the blinking cursor. What could possibly be the problem? When I take the added memory out, nothing comes up on the monitor. Visit our website regularly for FAQs, articles, how-to's, tech tips and much more http://nospin.com - http://nospin.org