The cd or dvd drive of my laptop not working since one month what is the problem and how can it b back to normal

Possibilities:
Some software you've installed has disabled it
The drivers need to be reloaded for some reason
The drive has physically failed and needs to be replaced

Quick try: run a System Restore and choose a date several months back... fingers crossed.

Start > Programs > Accessories > System Tools > System Restore

Remember to pick a date back a few months to restore to.