cd burning prob

[ssc1]

i have a nearly new advent pc with a separate cd-rw and i'm trying to put my pics onto disc which has been ok for the last month or so , but now when i try to get windows xp to put things onto the disc it says that there is not a disc in the drive even though i have put a new cd-rw disc in , i even tried a cd-r disc but it seems that the computor just cant see the disc in the drive , and i have tried the nero program that came with the pc but still the same , what am i doing wrong and could it be that the cd rewriter has gone tits up

[ssc1]

thanks people i tried some of this and then phoned the help line that sold me the pc and after uninstalling and running different discs in safe mode the computor still cannot see a disc in the drive and thats useing nero and the windows xp wizard and i was then told that the cd rewriter is at fault as it cannot see a disc. so an engineer is coming around tomorrow to replace said item , so thanks anyway for your replies.......