I need to install files on my Nokia N810 device by downloading the installation file through the USB interface and then running them locally from the tablet. Is it possible? If yes, please give a quick guide how can I do that.

Thanks!

First move the installation file to your tablet. Then open application manager, hit the menu button, go to application, and click install from file. Then find the installation file and follow the steps. If you have wifi it's easier to browse applications to install right from the applicaion manager.

If your computer has Bluetooth, sending files via Bluetooth to the tablet is also an option, and you don't have to have your USB cable with you all the time.

Just enable Bluetooth in settings, make sure your tablet is visible, and send it from your computer (you might want to pair your computer with your tablet first).

bluetooth may take a while for larger files, unless one have a 2.0+edr dongle at the pc end.

I hadn't thought of transferring files through bluetooth. So if I bought a bluetooth 2.0 edr dongle, is it easy to transfer files? If I'm within bluetooth range, can I access files on my pc from my n800?

yes, altho the details on how its set up will depend on the os used on the pc.

the N800 will show a bluetooth section in its file manager ones it and the computer is paired up. if the computer is then set up with a "share", the N800 should be able to read from it, or potentially even write to it.

I can't speak to what Windows will do when connected to the tablet. With Ubuntu Linux I can send and receive files with bluetooth from to both the tablet and PC. With the USB cable both the internal and external drive will mount and and open on my PC desktop. File and folders can be dragged and dropped on the desktop. On the tablet side the File Manager won't show those drives while connected via USB.

Note that the tablet recognizes .install and .deb files are to be opened with the Application Manager. When the tablet recieves one of these files via bluetooth there is a checkbox to open the file after transfer which in the case of .deb or .install open Application Manager for you.