mon gaveur ne marche plus

bonjour,
j'ai installé mon graveur Nero 6 grâce à un logiciel.
il a marché pour les 3 premières gravures de DVD puis plus rien: la gravure a échoué à 6X (la gravure des CD quant à elle marche très bien)
J'ai effectivement changé la marque des mes dvd vierges mais quand je réessaye avec ceux qui marchaient bien, sans succès...
alors j'ai désinstallé et reinstallé le logiciel mais toujours rien de mieux
il me dit:

Windows XP 5.1
IA32
WinAspi: File 'Wnaspi32.dll': Ver=4.71 (0002), size=45056 bytes, created 17/07/2002 08:20:56
ahead WinASPI: File 'C:\Program Files\Ahead\nero\Wnaspi32.dll': Ver=2.0.1.74, size=164112 bytes, created 26/10/2004 17:35:32
Version de Nero : 6.6.0.3 (Nero Express)
Graveur : <_NEC DVD+-RW ND-6450A> Version: 2.36 - HA 1 TA 0 - 6.6.0.3
Pilote d'adaptateur :<atapi> HA 1
Drive buffer : 2048kB
Bus Type : default (0) -> ATAPI, detected: ATAPI
CD-ROM : <_NEC DVD+-RW ND-6450A>Version: 2.36 - HA 1 TA 0 - 6.6.0.3
Pilote d'adaptateur :<atapi> HA 1

=== Scsi-Device-Map ===
DiskPeripheral : ST94019A atapi Port 0 ID 0 DMA: On
CdRomPeripheral : _NEC DVD+-RW ND-6450A atapi Port 1 ID 0 DMA: On

=== CDRom-Device-Map ===
_NEC DVD+-RW ND-6450A D: CDRom0
=======================

AutoRun : 1
Excluded drive IDs:
WriteBufferSize: 70254592 (0) Byte
ShowDrvBufStat : 0
BUFE : 0
Physical memory : 478MB (489904kB)
Free physical memory: 140MB (143428kB)
Memory in use : 70 %
Uncached PFiles: 0x0
Use Inquiry : 1
Global Bus Type: default (0)
Check supported media : Disabled (0)

10.12.2008
Compilation ISO
15:30:05 #1 Text 0 File Isodoc.cpp, Line 6168
Iso document burn settings
------------------------------------------
Determine maximum speed : FALSE
Simulate : FALSE
Write : TRUE
Finalize CD : TRUE
Multisession : FALSE
Burning mode : DAO
Mode : 1
ISO Level : 1 (Max. of 11 = 8 + 3 char)
Character set : ISO 9660
Joliet : TRUE
Allow pathdepth more than 8 directories : TRUE
Allow more than 255 characters in path : TRUE
Write ISO9660 ;1 file extensions : TRUE

15:30:06 #2 Text 0 File Reader.cpp, Line 127
Reader running

15:30:06 #3 Text 0 File Writer.cpp, Line 122
Writer _NEC DVD+-RW ND-6450A running

15:30:06 #4 ISO9660GEN -11 File geniso.cpp, Line 3286
First writeable address = 0 (0x00000000)

15:30:06 #5 Text 0 File Burncd.cpp, Line 3151
Turn on Disque entier, using DVD media

15:30:07 #6 Text 0 File DlgWaitCD.cpp, Line 256
Last possible write address on media: 2295103 (510:01.28, 4482MB)
Last address to be written: 2285609 (507:54.59, 4464MB)

15:30:07 #7 Text 0 File DlgWaitCD.cpp, Line 268
Write in overburning mode: NO (enabled: CD)

15:30:07 #8 Text 0 File DlgWaitCD.cpp, Line 2309
Recorder: _NEC DVD+-RW ND-6450A, Media type: DVD+R

15:30:07 #9 Text 0 File DlgWaitCD.cpp, Line 430
>>> Protocol of DlgWaitCD activities: <<<
=========================================

15:30:07 #10 Text 0 File ThreadedTransferInterface.cpp, Line 830
Setup items (after recorder preparation)
0: TRM_DATA_MODE1 ()
2 indices, index0 (150) not provided
original disc pos #0 + 2285760 (2285760) = #2285760/507:56.60
relocatable, disc pos for caching/writing not required/ required, no patch infos
-> TRM_DATA_MODE1, 2048, config 0, wanted index0 0 blocks, length 2285760 blocks [_NEC DVD+-RW ND-6450A]
--------------------------------------------------------------

15:30:07 #11 Text 0 File ThreadedTransferInterface.cpp, Line 1040
Prepare recorder [_NEC DVD+-RW ND-6450A] for write in CUE-sheet-DAO
DAO infos:
==========
MCN: ""
TOCType: 0x00; Session Closed, disc fixated
Tracks 1 to 1:
1: TRM_DATA_MODE1, 2048/0x00, FilePos 0 0 386269184, ISRC ""
DAO layout:
===========
__Start_|____Track_|_Idx_|_CtrlAdr_|_RecDep__________
0 | lead-in | 0 | 0x41 | 0x00
0 | 1 | 0 | 0x41 | 0x00
0 | 1 | 1 | 0x41 | 0x00
2285760 | lead-out | 1 | 0x41 | 0x00

15:30:08 #12 Phase 24 File dlgbrnst.cpp, Line 1832
Début de mise en cache des fichiers

15:30:08 #13 Text 0 File Burncd.cpp, Line 4038
Cache writing successful.

15:30:08 #14 Phase 25 File dlgbrnst.cpp, Line 1832
Cache des fichiers terminé

15:30:08 #15 Phase 36 File dlgbrnst.cpp, Line 1832
Début de gravure à 6x (8 310 Ko/s)

15:30:09 #16 Text 0 File ThreadedTransferInterface.cpp, Line 2596
Verifying disc position of item 0 (relocatable, disc pos, no patch infos, orig at #0): write at #0

15:30:09 #17 SCSI -1066 File Cdrdrv.cpp, Line 1176
SCSI Exec, HA 1, TA 0, LUN 0, buffer 0x03FB5000
Status: 0x04 (0x01, SCSI_ERR)
HA-Status 0x00 (0x00, OK)
TA-Status 0x02 (0x01, SCSI_TASTATUS_CHKCOND)
Sense Key: 0x05 (KEY_ILLEGAL_REQUEST)
Sense Code: 0x24
Sense Qual: 0x00
CDB Data: 0xAD 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x08 0x04 0x00 0x00
Sense Data: 0x70 0x00 0x05 0x00 0x00 0x00 0x00 0x0A
0x00 0x00 0x00 0x00 0x24 0x00

15:30:09 #18 Text 0 File DVDR.cpp, Line 5611
Drive: _NEC DVD+-RW ND-6450A
Book Type request: DVD-ROM
Changing the Book Type was finished successfully, return code 0

15:30:09 #19 Text 0 File DVDR.cpp, Line 5095
Drive: _NEC DVD+-RW ND-6450A
Book Type request: DVD-ROM
Changing the Book Type was finished successfully, return code 0

15:30:09 #20 Text 0 File DVDPlusRW.cpp, Line 608
Start write address at LBA 0
DVD high compatibility mode: Yes

15:30:26 #21 SCSI -1106 File Cdrdrv.cpp, Line 1430
SCSI Exec, HA 1, TA 0, LUN 0, buffer 0x0AD80000
Status: 0x04 (0x01, SCSI_ERR)
HA-Status 0x00 (0x00, OK)
TA-Status 0x02 (0x01, SCSI_TASTATUS_CHKCOND)
Sense Key: 0x03 (KEY_MEDIUM_ERROR)
Sense Code: 0x73
Sense Qual: 0x03
CDB Data: 0x2A 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x20 0x00 0x00 0x00
Sense Data: 0x70 0x00 0x03 0x00 0x00 0x00 0x00 0x0A
0x00 0x00 0x00 0x00 0x73 0x03

15:30:26 #22 CDR -1106 File Writer.cpp, Line 311
Erreur calibrage puissance

15:30:26 #23 Text 0 File ThreadedTransfer.cpp, Line 228
all writers idle, stopping conversion

15:30:26 #24 Text 0 File ThreadedTransfer.cpp, Line 222
conversion idle, stopping reader

15:30:26 #25 Phase 127 File dlgbrnst.cpp, Line 1832
Génération des cadres DVD de compatibilité supérieure

15:30:26 #26 Phase 129 File dlgbrnst.cpp, Line 1832
Génération des cadres DVD achevée avec succès

15:30:26 #27 Text 0 File DVDR.cpp, Line 5611
Drive: _NEC DVD+-RW ND-6450A
Book Type request: DVD+R
Changing the Book Type was finished successfully, return code 0

15:30:26 #28 Text 0 File DVDR.cpp, Line 5095
Drive: _NEC DVD+-RW ND-6450A
Book Type request: DVD+R
Changing the Book Type was finished successfully, return code 0

15:30:26 #29 Phase 38 File dlgbrnst.cpp, Line 1832
La gravure a échoué à 6x (8 310 Ko/s)


Existing drivers:
File 'Drivers\CDRALW2K.SYS': Ver=8.0.0.212 , size=2560 bytes, created 05/10/2006 03:42:42
File 'Drivers\ASPI32.SYS': Ver=4.71 (0002), size=16877 bytes, created 17/07/2002 07:53:02
File 'Drivers\PXHELP20.SYS': Ver=3.00.41a, size=36560 bytes, created 27/09/2006 22:53:22 (Prassi/Veritas driver for win 2K)
File 'Drivers\atapi.sys': Ver=5.1.2600.2180 (xpsp_sp2_rtm.040803-2158), size=95360 bytes, created 03/08/2004 22:59:44 (Adapter driver for rec)

Registry Keys:
HKLM\Software\Microsoft\Windows NT\CurrentVersion\WinLogon\AllocateCDROMs : 0 (Security Option)

merci pour votre aide!!