I would suggest an Archive & Install rather than a comple re-installation:
How to Archive & Install:
and this also:
BUT: Don't install older versions of Mac OS than what came with your computer:
Thanks for the reply.
But my problem includes :-
- I am not able to copy or paste anything anywhere.
- I can't even drag things anywhere.
- My Flash is not working, Because of which i can't see any video.
Now i had finally removed all the useful data ( except that came intially with system).
So, now i want to format it.
One important Point, My system intially came with 10.5.6 and now with the use of software update i had updated it to 10.5.8
Guide me then.