CD Burner not working

[icemanknoell]

I have an HP pos that was claimed to have been rebuilt.New windows XP pro,new drivers(cd-r,wr,and 3.5 floppy),etc...What I am having problems with is the fact that the cd-r/wr will not detected a blank disk to burn.It reads and plays cd's fine,but my burning program(windows media 9)won't recognize a blank disk.I've done all the trouble shooting with no success.The device manager says all my hardware is working properly.Frustrated,so I bought an external burner,exact same situation as before,doesn't recognize a blank disk but plays cds and dvds fine.Ok,so now I exchanged the drive with a drive on a computer I know works and it work on the good computer,and the drive from the good computer did not work in the pos computer,as was the same with the external burner.Anybody have an idea of what is wrong?
Also,I can not connect the pos to a broadband cable internet connection.I've done all the trouble shooting there as well.Shut down the firewall,and ran the set up wizard numerous times,adjusted LAN settings.I get an icon in my tray that says connection slow.Tried to repair and renew IP address nothing works.Any idea's on this.Oh,and I don't have a windows recovery disk so I can't reboot the system.