It sounds as if you have just used up the life of your CD-RW cd if you cannot remove or rewrite on it. CD RW cd's have a shorter life expectancy when compared with a CD-R cd because the CD is burnt at different temperatures. You can find out more about burning CDs and their life expectancy at
http://users.forthnet.gr/ath/axatis/FAQs/CDR/index
.htm#basic.
If
you have not used your CD that much and you don't feel that it has met its life expectancy it may be because you have bought cheap CDs to record on (and don't be offended if this isn't the case!) but sometimes if you buy poorer quality media it doesn't last as long.