Inspiron 9400 March 2007 - DVD Drive not recognized

Hi,

I have this laptop since March 2007 and it was working fine till last week. I had to reinstall WinVista twice in last year because of some crash. However the DVD drive was working. A few discs were not recognized by the drive since the starting. I kind of accepted this fault.

However, in last week, the DVD drive completely disappeared from my system. I mean I can't see it in explorer, niether in Device Manager nor even in BIOS Console. I did not do anything that can be classified out-of-the-normal at the point when this happened. One thing more - the drive working indicator LED glows continuously and I can't take out the drive by using it's eject button. Moreover, if I put the machine to "sleep" mode once and then wake it up, the DVD drive is again back in the explorer. However it can not read any DVD whatsoever.

I hope to hear from some of you who may have some knowledge on this problem.

Regards,