I installed eoffice 4.1 on my 8800. and sice then I have the sand glass turning: no telephone, no active button (after alt - Cap del the screen black and back with the sand glass) same story if I remove the battery.

What can I do?

I would remove the battery for several minutes. Then try rebooting again.

No change still with the sand glass after 15 minutes without battery.

So, placing the battery back in the device--all that happens is the hourglass spins? Let it spin about an hour and see what happens before you take more drastic measures.

Then, I would recommend reloading the OS... and wiping it as well.
How do I wipe the BlackBerry using Jl Cmder? - BlackBerryFAQ

Good luck.