My N800 Tablet just started indicating to that I have low memory and it is unable to log on to the internet and carry out normal functions. i did not install or do anything I just added some files to my memory card and this started popping up. What could I do to resolve this? When trying to open my PDF files im getting the response of "Not enough memory to display pages." Why? Can someone help me please.

First, make sure that those files are on the memory card and not in the device's internal flash memory (If you fill that ugly things will happen).
If that wasn't the problem, then restart the device.

Hey Thank, I restarted the device and my problem of low memory was solved. Thanks. Having done that now my PDF reader is not showing the pictures and scanned items on my files. So im asking you all experts again what should i do to rectify this?

How big are your memory cards? ALWAYS store everything it's going to use, the data, on the internal card....ESPECIALLY Maemo Mapper map files! Why it even stores anything in internal flash is crazy.

Anything you can tell the apps where you moved data to the internal SDHC card frees lots of memory for apps. Never store documents or movies or music or anything like that on internal memory.