Since I got 3 virus and many BSOD later, I ve got Windows 7 to work normally. (The system restauration and Chkdsk seems to resolve my problem)
I ran HiJackThis to verify and I got only one line that may be curious
O20 - Winlogon Notify: wzdiyin - C:\Windows\SYSTEM32\wzdiyin.dll
What do you think of it ?
Shoult I uninstall it ?