Crash écran bleu window 7

Bonjour,
Depuis 2 jours mon ordi crash et se redémarre tous seul , à chaque fois un écran bleu apparait mais j'ai pas le temps de voir ce qu'il est écrit . J'ai utilisé le logiciel WhoCrashed et voici le rapport :
Crash Dump Analysis
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Crash dump directory: C:\Windows\Minidump

Crash dumps are enabled on your computer.


On Tue 27/12/2011 23:54:54 GMT your computer crashed
crash dump file: C:\Windows\Minidump\122811-22171-01.dmp
This was probably caused by the following module: rdyboost.sys (rdyboost+0xA275)
Bugcheck code: 0xD1 (0x8, 0x2, 0x0, 0xFFFFFFFF86F3E275)
Error: DRIVER_IRQL_NOT_LESS_OR_EQUAL
file path: C:\Windows\system32\drivers\rdyboost.sys
product: Microsoft® Windows® Operating System
company: Microsoft Corporation
description: ReadyBoost Driver
Bug check description: This indicates that a kernel-mode driver attempted to access pageable memory at a process IRQL that was too high.
This appears to be a typical software driver bug and is not likely to be caused by a hardware problem.
The crash took place in a standard Microsoft module. Your system configuration may be incorrect. Possibly this problem is caused by another driver on your system which cannot be identified at this time.


On Tue 27/12/2011 23:54:54 GMT your computer crashed
crash dump file: C:\Windows\memory.dmp
This was probably caused by the following module: rdyboost.sys (rdyboost+0xA275)
Bugcheck code: 0xD1 (0x8, 0x2, 0x0, 0xFFFFFFFF86F3E275)
Error: DRIVER_IRQL_NOT_LESS_OR_EQUAL
file path: C:\Windows\system32\drivers\rdyboost.sys
product: Microsoft® Windows® Operating System
company: Microsoft Corporation
description: ReadyBoost Driver
Bug check description: This indicates that a kernel-mode driver attempted to access pageable memory at a process IRQL that was too high.
This appears to be a typical software driver bug and is not likely to be caused by a hardware problem.
The crash took place in a standard Microsoft module. Your system configuration may be incorrect. Possibly this problem is caused by another driver on your system which cannot be identified at this time.


On Tue 27/12/2011 23:53:24 GMT your computer crashed
crash dump file: C:\Windows\Minidump\122811-24531-01.dmp
This was probably caused by the following module: avgntflt.sys (avgntflt+0x12918)
Bugcheck code: 0xA (0xFFFFFFFF839FFFEC, 0x2, 0x1, 0xFFFFFFFF8289B2AA)
Error: IRQL_NOT_LESS_OR_EQUAL
file path: C:\Windows\system32\drivers\avgntflt.sys
product: AntiVir Workstation
company: Avira GmbH
description: Avira Minifilter Driver
Bug check description: This indicates that Microsoft Windows or a kernel-mode driver accessed paged memory at DISPATCH_LEVEL or above.
This appears to be a typical software driver bug and is not likely to be caused by a hardware problem.
A third party driver was identified as the probable root cause of this system error. It is suggested you look for an update for the following driver: avgntflt.sys (Avira Minifilter Driver, Avira GmbH).
Google query: avgntflt.sys Avira GmbH IRQL_NOT_LESS_OR_EQUAL





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Conclusion
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3 crash dumps have been found and analyzed. A third party driver has been identified to be causing system crashes on your computer. It is strongly suggested that you check for updates for these drivers on their company websites. Click on the links below to search with Google for updates for these drivers:

avgntflt.sys (Avira Minifilter Driver, Avira GmbH)

If no updates for these drivers are available, try searching with Google on the names of these drivers in combination the errors that have been reported for these drivers and include the brand and model name of your computer as well in the query. This often yields interesting results from discussions from users who have been experiencing similar problems.


Read the topic general suggestions for troubleshooting system crashes for more information.

Note that it's not always possible to state with certainty whether a reported driver is actually responsible for crashing your system or that the root cause is in another module. Nonetheless it's suggested you look for updates for the products that these drivers belong to and regularly visit Windows update or enable automatic updates for Windows. In case a piece of malfunctioning hardware is causing trouble, a search with Google on the bug check errors together with the model name and brand of your computer may help you investigate this further.