Packard Bell OneTwo M3700 PC boots up but no display

Can you post a picture of the machine?

Beep codes are nice but you have to know who makes the BIOS to use them. Check the RAM and see if it is loose.

Try this link
Packard Bell oneTwo M3350 / oneTwo M3351 / oneTwo L5350 / oneTwo L5351 All-In-One Computer Service Guide

Check to see that the memory module is installed correctly and that its working. you can do this via the bios setup screen.

That is an all in one computer. So, no those boards are not standard. You should be able to find a replacement board if you are needing it on ebay, or directly through Packard Bell.
And atx and matx are referring to motherboard size. (micro)atx boards are smaller, usually less feature rich, and more densely packed, but they are usually cheaper than the larger, roomier, usually more feature rich atx boards.

Maybe it is not getting cool enough cause the cooling fan is not working. You need to provide more info about at which point of booting up, it gets shut down.

add via USB an external keyboard, like me, because some keys are no more working on the bad Chinese used keyboard.!!

I have a similar problem with a Packard Bell OneTwo S PG4G1TU01 : when switching it on, it work a few minutes and suddenly shutdown, as a brutal power down. But the green light at the bottom still working. I have changed the extern power supply and now it work fine... The new power supply is a 90W model, not a 65W like the original one. Maybe it can help ?

put recovery or wincd disk in drive restart when screen says boot with cd click enter follow the steps
if can't boot from cd restart while continuosly pressing f7 startup options will appear high light cd or cd/dvd option
then should boot with cd

Hey, Blackchuck, try this
When you power up, try to get into BIOS and see what you get.
Let me know and we'll go from there.
Ron-