yes i dropped my n900 and now its catching on something when i open and close the slider :-(
its a dodgy chinese refurb that i got a couple of months ago so who knows what the build quality is like inside.

my question is whats under the screen around the bottom middle left area that could be catching? is it worth me opening it up to have a look? i dont want to break it completly.

Open it up. Sounds like something in the middle as un-located it's self.
Have a look at the repairing USB threads for dis-assembly.
While your at it re-inforce the USB too!

That happened to mine once (the fall, & the crunchy slider).
In my case, a screw under the screen was actually loose (it started unscrewing).
Fixed it by opening up the N900, screwing it back more tightly, & closing up the N900.

This video may help.
http://www.youtube.com/watch?v=aVEHm325-z8
Note: I didn't need to remove all 6 screws in video at time: 0:47, didn't need to remove the plastic bit at 1:16. Just be really slow & careful at 1:25, coz it's a bit tricky to put it back together there (the join between the screen & keyboard). At 1:25, you should be able to see the screws under the screen & screw them back tight.
It happened a 2nd time to me. Being a little fed up, I glued them in in the next round.

kh

that was exactly what happened! i only noticed it was the screw untill it got to the point where the slide wouldnt close at all.

thanks guys.