Lite-On SOHW-1673 won't burn

I have been using my Lite-On SOHW-1673 for one year without any problem, and the drive reads purchased cd’s and DVD’s normally. But the problem now occurs with CD-R’s.
I have allready burnt several CD-r’s with music, but the other day the files to be burnt maybe exceeded the maximum of the CD-R by some minutes. Normally, Nero 6 warns me that I should not continue, and I follow the warning. But this time there was no warning, and the burning was successfull.
The day after begining a new burning, Lite-On could find no CD-R nor read any burned CD-R.
I checked the CD-R on another computer where I burned it successfully.
What is the problem?
What can I do?

Hi,

can you try the drive on another computer, just to sort out system issues?
Please, check if pressed CDs can be read.
Also, get some bootable CD (I like Knoppix for this) and see if you can still boot from the drive. If that fails, too, then probably the drive has gone bad.

Michael