Ecran bleu de la mort et vista

Bonjour,

Cela fait depuis un certain temps que mon ordinateur redémarre soudainement et m'affiche un écran bleu de la mort !
Je possède un ordinateur portable ACER 5100 sous vista
AMD Turion64 Mobile Technology MK-36 (2.0 GHz, 512KB L2 cache)
ATI Radeon Xpress 1100
2GB DDR2

Voici ce message :

A problem has been detected and windows has been shut down to prevent damage to you computer.
DRIVER_IRQL_NOT_LESS_OR_EQUAL
If this is the first time you've seen this stop error screen, restart you computer. Il this screen appears again, follow these steps :

Check to make sure any new hardware or software is properly installed. If this is a new installation, ask you hardware or software manufacturer for any windows updates you mind need.

If problems continue, disable or remove any newly installed hardware or software. Disable BIOS memory option such as catching or shadowing. If you need tu use safe mode to remove or disable components, restart you computer, press F8 to select Advanced Startup Options, then select Safe Mode.

Technical information :
***STOP : 0X0000000D1 (0XFFFFFFF4, 0X0000000A, 0X00000000, 08BA6445A)
***athr.sys - Adress 8BA6445A base at 8BA02006, DateStamp 496d439a

Collecting data for crash dump...
Initializing disk for crash dump...
Beginning dump of physical memory
Dumping physical memory to disk : 100
Phsical memory dump complete
Contact your system admin or technical support group for further assistance

J'aimerais avoir de l'aide sur la signification athr.sys.
Je vous remercie d'avance.