I have suddenly started having problems with cd-rws today,files can't be copied using XP or Nerot,tried new discs no joy re-installed Nero no different even tried Deep Burner same result Error message from XP error in writing, message from D/Burner medium error, power calibration area error. Runnig XP with SP2 and all the updates. Nero is OEM with no updates been running with this for 3yearswith no problems, also tried restoring no joy there.
Rewriters are not the most robust longevity wise (see manufacturers' figures for failure rates) and it is likely that your drive has developed a fault.
But before you discard the drive (a new CD-RW drive is only around £10 to £15 these days, so a DVD equivalent would be more sensible future proofing wise), go to Device Manager, Uninstall the rewriter and then Reboot.
Try it again and, if it doesn't work, then it will most likely only be fit for the rubbish bin...:-(
The lasers in CD-RW drives burn out after a few years anyway because the beam has to be stronger when it writes a disc than when it reads a disc. Also the power calibration error is usually to do with the laser not getting enough power to burn to the disc. So if your drive is a few years old it may have just worn out so you should get a replacement. DVD writers only cost about £35 now.