What are the latest HP 740r DVD R/W drivers?

My HP M7257C Media Center P/C has developed a slight problem. Its main DVD drive, the HP 740r (not 740b) is no longer recognizing DVDs and has lost its ability to write to CD-Rs as well. It plays DVDs and CDs fine, but no writing, which is inconvenient as you can imagine. Poor HAL is out of warranty (go figure) and everywhere I look for drivers wants me to install their software for the measly sum of $29.95 and up. Any ideas? The driver it hs now is 5.1.2600.5512.