randomly ive been getting this problem with my n900 where when i hit the switch or activate the screen or slide it open the display will light up for maybe a second and then blank out again. it will then generally not respond to my attempts to get the display to come on again. if it does come on it will only come on for a second before blanking out again. it also appears that the touchscreen is still active when the display blanks out because it would seem that i hit something while the display was off because when it flashes back on something has changed. i usually have to reboot for it to solve itself. it has so far happened twice and both times it took two reboots to solve the problem. i havent installed or done anything new or different to the device lately. any ideas?

When diagnosing problems like these, it helps to backup your data and reflash to stock. If it is a hardware problem it will persist from that point. That being said, I can think of a few hardware things that would cause it. Having torn down my N900 to bare plastic twice to replace the LCD then the digitizer (touch screen panel), I've noticed quite a bit of less-than-stellar engineering.

Do you have these problems with the screen when the screen is slid up (keyboard exposed)? The flex cable is very fragile - I've torn one. The display would act fine with the keyboard open, but once it was closed it'd go nuts.

Start by reflashing, then just poke around and see if you can replicate it if the problem persists. If you need any assistance, send me a message. Cheers!