SIMS problem!!! (original version + unleashed expansion pack)

[Domino]

I got the Sims (original version) a few weeks ago, I installed the Makin' Magic expansion pack and played it for a few weeks. Got a bit bored of it so uninstalled them both and reinstalled the Sims with the Unleashed expansion pack. It worked fine for a couple of days but now when i try to load the game it gets up to the part where the phrases scroll across the bottom, it gets half way through then just cuts straight back to my normal screen. On the occasions i have got it to load (usually after i have restarted my comp) it lets me choose a house and then just stops running. I have no other programmes running at the time and my computer isnt online. Can anyone help??