Watch out! It seems there is malware that fakes Windows Genuine Advantage Notification and Validation Tool
See the topic at AUMHA (thanks to Microsoft MVP Steve Wechsler for the link). The HijackThis log show:
O23 - Service: Windows Genuine Advantage Validation Notification (wgavn) - Unknown owner - C:\WINDOWS\system32\wgavn.exe
Note that, the legitimate Windows Genuine Advantage Notification Tool is WgaTray.exe located in WINDOWS\system32 and there is no Windows Services for it! The said file is being requested for further analysis.