I've got an old system that I'm using for some CAD work.

The system is a Gigabyte GA 7ZX motherboard with Socket A for AMD Duron/Athlon processor; a VIA KT133/686A chipset, with support for PC133 SDRAM .

I did something very simple ---- I replaced the CPU Duron 900 with a Duron 1200 and I added a stick of 256 memory. I made sure that the CPU and memory pieces were compatible with the motherboard.

The machine will not pass the POST.

I took out the memory and put the old processor back in......no POST
I took all peripherals off line and added them one at a time.....no POST
I replaced the power supply......no Post
I replaced the motherboard with a brand new one exact model.....no POST
I pulled the video card and checked it.......no POST
I switched the old CPU back in.....no POST
I switched out the memory sticks one at a time....no POST

I'm stumped, any ideas.

Hi and welcome to the forum
Try configuring your system with a minimal setup, outside of the case on a cardboard box, (the motherboard box works the best). Motherboard, CPU & heatsink and fan, one memory module and one video card. Attach the Power supply to the motherboard, Attach a power wire to the video card, if the video card requires it. Connect a keyboard and mouse. Connect a case speaker at the front panel connector.
See if it will boot
Good luck

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Asus M4A79 Deluxe, Phenom II 940 BE, 20,770 3D06

Asus Moderator ~ My CPU Overheating Guide

Are you sure the new CPU is functional ?

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World's best Red Alert 2: Yuri's Revenge mod and Star Trek: Starfleet Command 3 mod: Overmind.ro

I've got the same motherboard (complete with G-Luxon caps), have you tried clearing the CMOS/BIOS? I've had boards behave similarly after little component tweaks finding they wouldn't then POST (yeah I'm talking about you KT3 Ultra2! ) clearing the setup configuration was the only solution that got the system up and running again for me

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