Well....at first i gotta say that.....i ain´t gonna be of much help....!!!
BUT I have experienced almost the same problem....with the difference in hardware....and that, the only thing i did was installing nero 5.5.3.0. burning software.....which didn´t work...so i removed it...and then the dvd and the cdrw-drives were missing ie. the drivers were´n there anymore !!!!!!!
I still haven´t a clue what caused this....and i had to format me d: and re-install my XP rc1......PHU!
sigh...
Hope to see a solution.....because I darn to say...i´m certain this will REAPPEAR!......