I could not able to select the tones.It needs to be reset to the factory level.Please help me to reset the Keyboard to the original status.?

Sometimes companies use the same sequence for all their synths...

Here is one to try:
How do you reset casio keyboard lk-60?
This is how. 'Turn keyboard of for 5 seconds then turn it bak on and play"e-flat,g-flat,e-flat,b-flat,g-flat,e-flat,g-flat" then turn keyboard of and unplug and wait 5 minutes then plug back in in,...
Note: It is NOT clear if you need to hold the notes down as you play them or press and release.

Here is another for Casio:
From the FILE menu, select INITIALIZE to select the sub menu. Select the SYSTEM option to return the keyboard to its factory settings. Keep in mind that this operation will delete anything that is stored in the keyboard memory. When you see the InitSys? on the screen, select YES. I hope this helps......

I could not find anything specific to the 810.

If these don't work, then the way to reload is via the MIDI port which will accept Sysex commands and data. You can probably find a data dump online for this at the Casio site..
You will of course need to have a MIDI port on your PC.