whenever i try to uninstall my MS office 2010 [tech. preview] it gives me an error , uninstaller is corrupted , try to run uninstaller from the original setup.
If i do that, it doesn't give me an option to uninstall it !
I tried to reinstall the whole MS office 2010 [tech. preview] from the same setup again, but though failed ! the same here was in front of me 
:(
@aarsh
pseudocoder's link is the current recommended solution.
Make sure you know exactly what Windows version you have and whether this was an upgrade to an existing Office version. You will need the media and licence to reinstall a previous version.
Don't forget to back up all your data and to make a backup of the Registry before making big changes.
@methyl :
I am about to visit that link , but first I would like to tell that Yes, it was an upgrade.
I would like to ask you also that how to take the back - up of registry ?
The quickest is to create a "System Restore Point".
Find out how to do this by searching the Microsoft Help for "System Restore Point" which should be somewhere on your Start menu (or the Vista equivalent).
One of the many sites which describe backing up the Registry by various methods is below. I'd treat this sort of site as background reading then look up the exact method for your Windows Operating System (whichever that is?).
How to Backup the Registry in Windows 7, Windows Vista and Windows XP
find the folder, erase it. then erase all the icons.. just make sure you know what your doing
This is why I never, ever, ever install Microsoft upgrade products. Burned far too many times, or seen people burned. They almost always cause strange errors, either immediately, years later, or both.