HP DVD writer works CD writer doesn't

I have a 2 year old HP Pavilion a350n that came with a CD/DVD Writer. Since then I have upgraded to XP service pack 2 (Windows XP Home Edition SP2) And after that the CD writing functionality has just stopped working. I can read/write DVDs fine, but I can only read CDs. The error message that I get is just something along the lines of "insert a blank media" and even though I do, it just doesn't recognize that a blank CDR is in it. (Yes I've double checked the right media-- I used to burn on the same CDRs before on the same drive)

Any advice would be much appreciated.
Thanks!

-G
Relevant stats- HP Pavilion a350n, Windows XP Home edition SP2;
DVD writer - HP DVD Writer 300c

Have you confirmed the device works in another PC.