Prob with cd-writer

From last few days m getting a strange prob while trying to burn CD using my CD writer. i can play audio and video CD in the drive, but when i try to burn CD it says" there is no CD in the drive, although actually there is one. if i restart the computer ,sometimes after restarting it starts working, sometimes not. when the writer doesnt work, at that time when i insert a CD in the drive the CD folder doesnt open automatically and the E: symbol doesnt change to the name of the CD (in "my computer"). but if i click on e drive the CD opens and i can see the files if the CD already has some file.
plis help me in solving this problem..
regards
Geneman