I am trying to figure out why my computer is hanging. One minute the computer is fine, the next minute the mouse doesn't move and nothing works. I am running an 850mhz Athlon T-Bird and I know they are notorious for high heat. I pulled the heat sink off and it looks like it could use some of that heat transfer grease. Most of the old grease had settled on the sides of the square metallic chip in the center of the CPU. I'm just not sure if the CPU temp is spiking during operation and causing the system to hang? I was also thinking that the RAM was causing it to hang. I have two sticks in there, one is a regular 128MB stick of PC133 and the other is some kind of special RAM that will read 256MB PC133 for certain chipsets and only 128MB for others. I'm sure you know what I am talking about. At any rate I ran the system with one stick, it hung, then with the other stick, and it still hung, so I don't think it is the memory. I also pulled all of the devices out like sound card and so forth and they aren't the culprit either. So what do you think? Could a hard drive cause that? What else is their to check? I know it is not software related because this is a fresh copy of Windows 98 and the damn thing kept hanging during the installation of Windows XP Pro, so... Any suggestions are always appreciated!