iPhone not recognized on my Desktop

Hello,

My PC : HP Elite m9361.ch Vista X64 Edition Familiale Premium
My iPhone : 3GS 16Mo, OS 3.1.2
Itunes : 9.0.2.25

Since few days, I can't see anymore my iPhone under my Desktop (Windows Explorer).
If I connect it to the USP 2.0 port :

OK :
- iTunes see my iPhone, synchronisation is OK, everything is OK with iTunes.
- Application as iPhoneBrowser 1.9.3.0 see it, folder DCIM too,
I can transfer pictures with this application.
- in Devices Managment, I see under Mobile Device "Apple iPhone", it seems OK, in Blue.

NOT OK :
- iPhone doesn't appear anymore in the desktop (windows explorer) when I connect it.
I hear 2 sounds when I connect my iPhone.
I can't see the folder DCIM anymore.
- I can import token pictures on my iPhone with HP Essentiel, Windows Pictures, etc,
but not I choose "Open with Windows Explorer" or "Import Pictures with windows",
I receive an error message.
- I tried to desinstall the driver, and then to reinstall it, but a problem appear:
The driver installation process start, it tells me that drivers are found under Windows update,
but then I receive the error message :
"The class installer has denied the request to install or upgrade this device".
At that point the driver installation apears to be aborted,
Then i have a yellow triangle for this device in the managment console.
However I can communicate with the iPhone with iTunes and iPhoneBrowser for exemple.
I must using "system restore" to recover this bug in the managment console
and to have this device OK (no more in yellow).

Can anyone using Vista X64 tell me :

- About the following registry key :
[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Class\{4D36E967-E325-11CE-BFC1-08002BE10318}]
Is this key present ?
Is there an Upper or lower filter on this key ?

- Wich drivers are installed for this device ?
I have the following drivers shown for this device in the managment console :
C:\Windows\System32\WpdConns.dll
C:\Windows\System32\WpdMtp.dll
C:\Windows\System32\WpdMtpUS.dll
C:\Windows\System32\drivers\WpdUsb.sys
C:\Windows\System32\drivers\WUDFRd.sys
C:\Windows\System32\drivers\UMDF\WpdMtpDr.dll
Are others drivers present ?

- What about the path the following directory :
C:\WINDOWS\System32\DRVSTORE\usbaapl_872A2434B7205D4BD84BBE53811BDCE15F347D5B
Does this directory exist ?
Wich files are present in this directory ?

Thanks for the help and the attention.
(and sorry for my bad English, I'm french speaking)