Thanks for reply. Full scan showed nothing and the disk was defragged beginning of this month. No recent downloads or strange happenings.
Looking at the event viewer it shows a "critical" event with an event id 100 - Boot Performance Monitoring a few days ago. In general it says "Windows has started up: Boot Duration : 113280ms IsDegradation : true Incident Time (UTC) : 18/09/2010 20:45:47
In detail
EventData
BootTsVersion 2
BootStartTime 2010-09-18T20:45:47.827Z
BootEndTime 2010-09-18T20:49:06.086Z
SystemBootInstance 769
UserBootInstance 743
BootTime 113280
MainPathBootTime 29030
BootKernelInitTime 26
BootDriverInitTime 2511
BootDevicesInitTime 3467
BootPrefetchInitTime 39634
BootPrefetchBytes 523894784
BootAutoChkTime 0
BootSmssInitTime 10572
BootCriticalServicesInitTime 546
BootUserProfileProcessingTime 974
BootMachineProfileProcessingTime 30
BootExplorerInitTime 6967
BootNumStartupApps 21
BootPostBootTime 84250
BootIsRebootAfterInstall false
BootRootCauseStepImprovementBits 0
BootRootCauseGradualImprovementBits 0
BootRootCauseStepDegradationBits 9437184
BootRootCauseGradualDegradationBits 9437184
BootIsDegradation true
BootIsStepDegradation true
BootIsGradualDegradation true
BootImprovementDelta 0
BootDegradationDelta 57091
BootIsRootCauseIdentified true
This "critical" event id 100 appears regularly on the log going back to September 2008. There are also logs of another Boot Performance Monitoring Event 101 which is a "warning".
Tried the link to the online Microsoft Technet but no results.
Anyone know what this means??