Your computer is a bit ... old. I knew this would happen to someone, but it looks like your computer doesn't support SSE2, only SSE. But it was kind of hard to find information on that processor. Every computer made in the last <large number of years> has supported SSE2 though.

Are you using Powder-legacy.exe? That was deprecated/removed because it was having strange issues with particles going through walls, and having two versions of TPT was confusing people.

I will try compiling a version tomorrow that might run for you. If it works, then good you can keep using that. It won't be officially supported though (you probably won't get updates in game), but it isn't that hard for me to compile a new -legacy version every time there is an update.

Well FINE

https://dl.dropboxusercontent.com/u/43784416/PowderToy/releases/TPT%2091.3%20no%20sse.zip

I forget things sometimes :P. Hopefully this runs, I compiled it in visual studio without sse2. The fact that it is compiled with visual studio will also probably make it faster (although the sse2 potential speed boost will be gone).