15" PB not recording CDs.

Hi!
I have a problem with my 15" 800 Mhz PB, with Combo-drive. It refuses to record CDs. It reads recorded and audio etc. disks, but inserted media (CD-R's or RW's) are just being chewed for several minutes and then ejected! No Toasting, no iTunes burning. Could You suggest something?
Thanks, Nik

bad news...

Thanks for replying.

My faithful PB worked fine since it was bought (a top of the line model then...)
Maybe it's just time for replacement... Or switch? (bad joke)
Apple Care is over I'm afraid.
What kind of a drive can I get? Is there a faster loading CD-RW or Combo? Or I can only replace it with the same slow-loading-not-that-impressive at all Combo it came with?

Thanks again. Nik