MOSS upgrade issue - SPAdmin service cannot start

Cannot start service SPAdmin on Computer

Cannot start service "SPAdmin" on computer after running SharePoint Product and Technologies Wizard

Step 1
On the machine where psconfig failed to start the SPAdmin service run:
%commonprogramfiles%\Microsoft Shared\Web Server Extensions\12\BIN\psconfig -cmd upgrade -inplace b2b -wait -force
Step 2
Modify the service timeout values in the Registry:
HKLM\SYSTEM\CurrentControlSet\Control add/modify DWORD value ServicesPipeTimeout to 60000 (60 seconds)
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control add/modify STRING value WaitToKillServiceTimeout to 120000 (120 seconds)

http://blogs.technet.com/b/wbaer/archive/2007/10/15/kb934525-troubleshooting.aspx