Thanks for the reply. I've got it wrapped up and in some rice at the moment and will see what it is like in the morning. I don't really think it's a liquid problem, but I suppose there is a long shot some moisture is in there from somewher, (from rain or something, even though I haven't had it out of my pocket in the rain), so am trying the solution for that first.
If nothing changes then I will have to get fiddly with the x terminal and perhaps try installing/un-installing some apps. I've had Geeps for a couple of weeks, but this was just the first time I actually got round to using it. I had also recently updated 2 things, which I can't remember now,in the morning.
It's still baffling how it happened. It's like there is an invisible finger pressing on the desktop somewhere, if I had to say where, it would be at the right of the screen, possibly 'off the screen' past the bottom right corner, if that makes any sense.

Hi All

The touch screen on my N900 completely stopped responding yesterday afternoon.
I re-flashed it (both PR 1.2 and PR 1.3) but this didn't fix the problem.

I then took the phone apart and disconnected both the screen and touch screen ribbons.
I blew out all the dust and dirt and put it back together.

This seems to have fixed the problem as my touch screen is now nice and responsive again.
I suspect the ribbons either had a bad connection or some dirt got in there.

In hind-sight, I wish I'd done this before re-flashing my N900 as I lost all my files (couldn't press the "Mass Storage" button and hence couldn't back stuff up).
Hope this helps people. ; )

How easy/hard was it to take apart the screen? And would it be obvious to nokia once it was sent back that it had been opened?

It's not too hard, but the ribbons are quite fiddly. There's plenty of videos and articles on the web on how to do it. Just Google them.

I wouldn't recommend opening it if you're at all worried about voiding you warranty.

That said, a good start would be to minimise signs of damage. Make sure you use a good quality PH00 screwdriver with a proper handle and be careful with the screws so as not to damage them. Also, always use some thin plastic to pry things apart (special service tool, piece of plastic, guitar pic, etc.) as anything harder will scratch or damage things.

Thanks- sounds like it might be easier to just send it in to get fixed/replaced. It's still in warranty and I haven't dropped it or spilled anything on it, so why not let nokia fix it. I just don't want the hassle of being without it again
Took it out of the rice earlier and it's still the same. Something inside it has gone. I wasn't 100% when I got this replacement in the first place. I knew it was a refurbished one, and that any of us that send things in to get replaced are just being given each others phones with minor fixes, so anything it had problems with before might come up again. It's really annoying that just when I was feeling happy with living with the slightly sliding keyboard ( it came like that- and it fixes the keyboard frame at the bottom whenever it pops out- might be some new "feature" I've not heard about)) - that it goes and breaks on me

UPDATE-

Turned it on this evening and ater initially thinking it was the same I swore at nokia and was about to go fill in the form to return it to be fixed. So, I wanted to try and get to x-terminal if I could and it just suddenly started working properly,
Weird huh?
The magical rice god has done it again. Thank you oh mighty one for accepting my technological offering and returning it anew.

All praise the Rice God

PLEASE helP!!!!!!!! MY Nokia N900 touchscreen reacts sporadically, what can i do please

Ok! I'm having screen problems since I turned my n900 on and get stuck on de lock code screen.
I can't type any numbers....

Now I'm trying the rice thing....

The rice thing didn't work for me! :-(

I've the exact same problem. Rice god failed me, and reflashing fiasco+emmc didn't work either. I'm stuck on entering the security code with a non-responsive touchscreen.