Verifique o Event Viewer
do Windows.
Windows Logs > System
Isso pode ajudá-lo a adivinhar qual aplicativo causa a reinicialização. Algo como:
The process C:\WINDOWS\system32\shutdown.exe (PCNAME-PC) has initiated the restart of computer PCNAME-PC on behalf of user NT AUTHORITY\NETWORK SERVICE for the following reason: No title for this reason could be found
Reason Code: 0x800000ff
Shutdown Type: restart
Comment: