ok, i have disable the UAC, tried the system rapair tool which doesnt see anything wrong with my computer
from the event viewer i get 2 errors
the first is an application error
Faulting application svchost.exe_MSiSCSI, version 6.0.6001.18000, time stamp 0x47919291, faulting module ntdll.dll, version 6.0.6001.18000, time stamp 0x4791adec, exception code 0xc0000374, fault offset 0x00000000000a6e97, process id 0xa38, application start time 0x01c9011ace10f09f.
2 minutes later there is another WMI error
Event filter with query "SELECT * FROM __InstanceModificationEvent WITHIN 60 WHERE TargetInstance ISA "Win32_Processor" AND TargetInstance.LoadPercentage > 99" could not be reactivated in namespace "//./root/CIMV2" because of error 0x80041003. Events cannot be delivered through this filter until the problem is corrected.
any idea? thanks