is this AT or ATX?

it's mom's compaq. it's a micro version of one of these. i can't tell on the PSU if it's one or the other. it's a 1Ghz P3. came with a 700 P3. i want to know if it's ATX to see if i can just buy a motherboard CPU and ram to upgrade this peice of crap to something a little stronger.

What do the connectors look like to plug it into the board? That will help determine the answer

2 connector =at

1 big one =atx

1 big one and one 4pin small one = p4 atx

Did they actually make at boards that support a gigahertz processor? I thought they stopped at at about 600 hundred or so.