Ok, I will start from the beginning in order to try to give all necessary information. I was given a used Acer Extensa 4620 laptop about a year ago when my PC went kaput on me. It had a 160GB HDD and the OS was XP. Well a few days ago I was cleaning out some old programs I never use because space was getting slim on there. No vital programs or anything (as far as I know). But I was also trying to install Nero because I was having burning issues with my usual DVD burning program. There were rumors that the version of Nero I was downloading had a virus on it, but most people said that was a false positive that virus scanners were pulling up because of the KeyGen. Anyways.... the laptop slowly died on me. At first, it stopped loading completely. Anytime I tried to do anything with a Windows folder, the computer would freeze up and I would have to reboot by pressing and holding the power button. Then I started to notice that less icons in the bottom right were loading when I would reboot. I tried to run Spybot S&D and it ended up freezing. AdAware pulled up no problems. I ran Norton 360 and it did not find any viruses either. I then ran multiple disk checks and such because the laptop prompted me to because of the way I had to reboot. I knew there was something wrong. Well, after a few of the bad reboots, I started to just get the "black screen with the blinking white underscore" issue that I have read about here. I decided that even though it would suck to lose what I had on my hard drive, I might as well reformat it with an old XP Disk I have. I pop it in, and I change the order in BIOS so it boots from the CD/DVD Drive. Everything starts fine with it, but then it says it cannot detect my hard drive, check to make sure it's plugged in fine, etc. Several people on this board seem to have had this problem, but none of them are exactly the same as mine. Anyways, I figure it's a bad drive at the time, and I go out today and buy a 500GB Western Digital SATA HDD to replace the "bad" Hitachi 160GB SATA HDD. Both are 5200rpm but I doubt that matters. I get home and pop the new hard drive into the laptop and start up the XP disk.... I get the same message. It cannot detect the HDD, so it F3 quits the installation process. Now I believe it's not an issue with the old HDD, but with something else. The motherboard maybe? I tried to run the Recovery function on the XP Disk, but it cannot detect the HDD to recover anything. I have access to another laptop right now (obviously, right?) but it is not mine so I cannot do much with it to test out my non-functioning one. I burned the boot disk that Kim mentioned in another "black screen with a blinking white underscore" thread, but it didn't do anything. I have read several of the "change the SATA whatever in BIOS" solutions, but since I am not trying to downgrade from Vista to XP like most of those people were, I already had XP running, I don't think it's a SATA driver issue. Also, I don't have a SATA/RAID/IDE or whatever option in my BIOS. The BIOS does recognize the HDD though. Both the new and old one. I have re-seated the HDD, but I will try with the RAM as well after I post this. Should I take back the new HDD and get a refund so I can afford to have a pro look at the laptop, or should I just go try to win more money at poker and buy a better laptop than a POS Acer? Or does anyone else have a solution?