I am running Windows 7 Professional, 64-bit.

I am running a backup-over-the-internet software client which depends on the Volume Shadow Copy Services running.

Since I installed Service Pack 1 (or rather, didn't object when Windows Update forced Service Pack 1 on me) the backup service is failing to back everything up because VSC isn't running. Most of the time it fails to back up such noise as the Security Essentials database or the Messenger Live contact list -- stuff I really don't care about -- but I don't want to fall into the trap of accepting an Error-state backup as "normal".

At the recommendation of the backup software, I have set the VSC service startup mode to be Automatic.

When I look in the Event Log, System channel I can see at boot time:

The Volume Shadow Copy service entered the running state.

...and then two or three minutes later:

The Volume Shadow Copy service entered the stopped state.

How do I figure out why VSC is stopping?

At the suggestion of the backup vendor, I have already followed the suggestions from http://support.microsoft.com/default.aspx/kb/940184

net stop SENS
net stop EventSystem
net start EventSystem
net start SENS
net stop COMSysApp
net stop SwPrv
net stop VSS

cd /d C:\Windows\system32
regsvr32 ole32.dll /s
regsvr32 oleaut32.dll /s
regsvr32 vss_ps.dll /s
vssvc /register /s
regsvr32 /i swprv.dll /s
regsvr32 /i eventcls.dll /s
regsvr32 es.dll /s
regsvr32 stdprov.dll /s
regsvr32 vssui.dll /s
regsvr32 msxml.dll /s
regsvr32 msxml3.dll /s
regsvr32 msxml4.dll /s

net start SwPrv
net start VSS
net start ProtectedStorage

...and per http://support.microsoft.com/kb/940184 I have deleted the key tree

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\EventSystem\{26c409cc-ae86-11d1-b616-00805fc79216}\Subscriptions

I have also run chkdsk /F and chkdsk /R on both permanent hard disks.

(I had a similar problem with another computer (same OS, same failure, same start point after SP1 install) but the problem went away when I forced Volume Shadow Copy Services to Automatic startup rather than Manual. I did not have to resort to following the Microsoft KB instructions.)