Installing a new CPU/motherboard/RAM. Basically taking out a Pent III 1GHz and 256 SDRAM and replacing it with an Athlon 2.17GHz and 1.24GHz DRAM. The new motherboard is an Asus A7N8X. Now I'm fairly certain I have everything connected properly, power supply, single hard drive, single CDROM, single floppy drive. Go to fire the beast up and for some reason its not wanting to load Windows XP. No idea why. I've set everything in BIOS according to the motherboard manual. Also, after a short time, the computer shuts itself off. I'm fairly certain this is because the CPU is overheating. Why that is though I'm not certain, I've got two fans on it and both are working. If its the CPU overheating then I need more fans, if not though what else could it be? Thanks in advance.

Did you replace the hard disk with a new one or have you put the old hard disk back in? If you put the old hard disk back in, did you reinstall Win XP? If not, you will need to do it. You see when you install an Operating system, it will look at your whole system (ie your motherboard),and keep that information in memory. Now if you have just installed a new MBoard and put the old HD back in it will not boot up, this is beacuse when the OS loads it will looks for the old motherboard and if it doesnt find it, it wont load. This is expecially true of Win XP. As for the overheating problem with the CPU, there is probably bad contact between the cpu fan and the cpu. Take the fan off, check the bottom to see if you have forgotten to take the sticker off, if you have, add some thermal paste and re-connect it will the CPU, making sure both have good contact with each other. Good luck.

Bleidd: As far as the system shutting down, reseat the heatsink. Make absolutely sure it is sitting flat on the CPU. Also verify the CPU fan is connected to the fan header designated for the CPU fan. If there is no RPM signal coming across the RPM wire of the CPU fan header on the motherboard, many motherboards will shut down the system to prevent CPU damage. "...for some reason its not wanting to load Windows XP." Please give us more details. Does the CD spin up? Does the activity LED light? Do you have the BIOS set to boot from CD? Are you sure the IDE cable is connected properly (in relation to pin 1) at both ends? Have you tried reseating the IDE cable at both ends?

I am not too familiar with XP, but I just fired up a new 2000+ system this weekend and my harddrive was not detected, either. So I tried another older drive and it came up right away, on Windows 3.1! I finally got the drive going that I wanted to use and had te FDISK and reformat and reinstall Win98. So each OS may be a bit different. I would definitely do a clean install.

Best way as PC Bob said is to do a clean install.