Photoshop CS4 crashes NO MATTER WHAT I DO?!?

[Chelsea G]

I recently had to get rid of CS3, long story, won't even get into that. I tried multiple things to keep CS3 because I absolutely despise CS4, but nothing worked, so I had no choice but to upgrade to CS4. Well, now, after HOURS of uninstalling CS3 and installing the loathly CS4, all it does is crash! I open it, sometimes it will be fine for a minute, the moment I try to open a new document (whether it's file > new or just opening some picture I already have saved) it crashes. It's driving me insane. And that's even if I'm lucky. It keeps crashing as soon as I open it, too. I've rebooted and reinstalled and no different. I don't know what I'm "running" my mom and brother have taken care of all of the technical things with my computer, I just know it's Windows something. Please, I NEED Photoshop, people pay me for my graphics and I have orders to fill and I have a picture I need to edit a family member and another one my mom hates me for not editing sooner for my great grandma -.- I'm going crazy here!