I apologize in advance if I posted this in the wrong area. Figured it would be close to what my problem may be. And if there is a thread similar that already exists. But I'm stumped. I have a self built computer (about 5 years old or so). I want to exaust all my options before I spend money on rebuilding this system. Here is what I have... Mobo: Gigabite GA7NNXP Ram: 1each centon 512mb PC2700; 2 each centon 256mb PC 2700. (bought 1g Kingston to trouble shoot the problem. same issue no matter which combo of ram) Vid card: Nvidia G force- 5500 Processor: AMD XP (I believe 650) Pwr Supply: ANTEC 350 watt DVD Writer: HP DVD 1170 HD: 160G Western Digital Cooling: 3 80mm fans and a large one on the top center of the case. All working. OS: latest windows XP release Problem... I started having a problem with the system freezing on me. I would go on line and check email or something similar, and it would freeze. I cant even CTL/ALT/DEL out of it, I have to shut it down. It looks like I am looking at a screen shot. You cant do anything, no cursor movement. Nothing. I totally erased the hard drive and started from scratch. When I would get to the license agreement on the installation. The system would shut down and and I would get 4 long beep tones alternating in pitch. High-low-high-low; then shut down. I pretty sure thats a DDR error or something like that. I disconnected everything except the minimum to run, same thing. I stopped messing with it for like a day or so, tried again (this is with the kingston ram) and things seemed to be fine. Windows installed like it is suppose to. Figured, problem solved. Not so much. I got online to download Mozilla or something, and as soon as the download was finished, everything froze. Right now as it sits, the kingston ram, is installed (brand new) and the minimum. I even disconnected the DVD drive, and the thing still locked up. Like I said if this post is in the wrong place or a similar thread is already active. I apologize. Thanks. Hopefully I gave enough info.