Help....

My N900 seems to have a problem with the memory....

I am unable to take photos or video, as i get the folling error;
'Memory not accessable. Unable to save content'

It is also the same for the browser, I cannot save photos etc, as I get the following error;
'Not allowed'

I tried installing a Micro SD card, so I could save to that and use the camera, but it is not showing up at all in the file manager, nor the camera options....

In Settings I have tried;
'Restore original settings'
'Clear device'
And I also tried reverting to a backup...all with no success.

All files I have on the memory arel still there, still accessable, and I have plenty space available....I just dont appear to be able to save anything new, from any source/using any app

Any suggestions?
If I cant get this fixed...its bye bye N900.