Ask the Experts / RCT2 Query

I recently re-installed RCT2 onto my comp, which isn't exactly the fastest or most brilliant in the world.
I've come across an interesting problemo though...

The game installs fine. I also install Direct X 9 or whatever version it is. All that's fine.
The game loads into the intro screen fine.
The problems starts when I go to start a new game. If I pick a new scenario, the game crashes. If I go into the Scenario Editor, I can pick out all the scenery and objects, but the game crashes when trying to load the actual park when finished.
I can however, use the Rollercoaster Designer without hassle, infact, it runs quite smoothly.

It's kinda pissing me off, as I'd really like to BUILD stuff aswell...

Can anyone suggest what I need to fix this, such as a patch or something, or am I well and truly stuffed?

What? No one wants to help?

Prolly no one's heard of this before. I'm not sure what to do.. try reinstalling again?

I'm kinda stumped, to be honest. Sorry.