i was updating latest version of itunes, now its corrupted or not installed properly, i dont want loose anything . What should i do, pls help!

First make sure to make copies of all *.ITL and *.XML you can find under

My Documents\My Music\iTunes and ALL Sub Directories and store them in a safe place.

These files (mainly the *.ITL file) holds the info for your Database.

Then try a uninstall

http://support.apple.com/kb/HT1923

and then try to install again.

Mae sure that after you uninstall you reboot your computer.