WEIRD DVD burning porblem

Hi there,
I have a Toshiba laptop with MATSHITA DVD-RAM UJ 831S. It can record on DVD±R, and I have used it not once. Yesterday it suddently stopped being able to burn on DVD+R or CD-R. I am still able to burb on DVD+RW or CD-RW. I do not have available DVD-R to test the other formats, but itseems that the drive can burn RW discs but not the plain recordable ones. This happened out of nowhere, I hadn’t installed any new software or cahnged any settings on the drive. I used NERO 7 ULTRA and SONIC RecordNow, with the same result problem. The DVDs that I wasted trying to figure out the issue are from the same Verbatim pack I have used before, so I do not thing it is a bad DVD batch issue.
In Nero, it starts burning, goes on for about a min and then stops with an error message. Nothing descriptive really. I noticed that the buffer level is completely empty, while it was always full when the successfull burning was possible. I reinstalled the SONIC RecordNow and it was no help. I have no clue what’s going on and I hope you can help me.
Please, respond ASAP.
Thanks a lot for the help.

Then clean the drive…