Help with my NEC ND 2510A DVD Burner?

I was able to burn both +/- DVD's with my NEC ND 2510A DVD Burner up to about 3 months ago. All of a sudden now I can only burn +, I must have changed somthing but I can't figure it out. I am at best a novice with computers so any help would be much appreciated. I have an Emachine T3256 with an AMD 3200+, 160gig HD, DVD +/- RW 8x double layer DVDRW. 1.024 gig memory. I use Nero. Error log : [16:56:39] %26lt;---MT---%26gt; 4:56:36 PM#23 SPTI -1046 File SCSIPassThrough.cpp, Line 323


[16:56:39] %26lt;---MT---%26gt; D: CdRom0: SCSIStatus(x02) WinError(0) NeroError(-1046)


[16:56:39] %26lt;---MT---%26gt; Sense Key: 0x05 (KEY_ILLEGAL_REQUEST)


[16:56:39] %26lt;---MT---%26gt; Sense Code: 0x30


[16:56:39] %26lt;---MT---%26gt; Sense Qual: 0x05


[16:56:39] %26lt;---MT---%26gt; CDB Data: 0x53 00 00 00 00 00 19 DF 60 00 00 00


[16:56:39] %26lt;---MT---%26gt; Sense Area: 0x70 00 05 00 00 00 00 0A 00 00 00 00 30 05


[16:56:39] %26lt;---MT---%26gt;


[16:56:39] %26lt;---MT---%26gt; 4:56:36 PM#24 CDR -1046 File ThreadedTransferInterface.cpp, Line 1799


[16:56:39] %26lt;---MT---%26gt; Illegal disc


[16:56:39] %26lt;---MT---%26gt; D: _NEC DVD_RW ND-2510A


[16:56:39] %26lt;---MT---%26gt;


[16:56:39] %26lt;---MT---%26gt; 4:56:36 PM#25 TRANSFER -27 File ThreadedTransferInterface.cpp, Line 1799


[16:56:39] %26lt;---MT---%26gt; Could not perform start of Disc-at-once


[16:56:39] %26lt;---MT---%26gt;


[16:56:39] %26lt;---MT---%26gt; 4:56:36 PM#26 Phase 38 File APIProgress.cpp, Line 278


[16:56:39] %26lt;---MT---%26gt; Burn process failed at 2.4x (3,324 KB/s)


[16:56:39] %26lt;---MT---%26gt;


[16:56:39] %26lt;---MT---%26gt; Existing drivers:


[16:56:39] %26lt;---MT---%26gt; File 'Drivers\CDRALW2K.SYS': Ver=8.0.0.212 , size=2560 bytes, created 8/19/2005 5:00:00 PM


[16:56:39] %26lt;---MT---%26gt; File 'Drivers\PXHELP20.SYS': Ver=3.00.33a, size=36528 bytes, created 8/24/2006 10:47:00 PM (Prassi/Veritas driver for win 2K)


[16:56:39] %26lt;---MT---%26gt; Registry Keys:


[16:56:39] %26lt;---MT---%26gt; HKLM\Software\Microsoft\Windows NT\CurrentVersion\WinLogon\AllocateCDROM... : 0 (Security Option)

Help with my NEC ND 2510A DVD Burner?
you probably just bought a batch of bad discs,