win 2k3

I am working in a machine with win 2k3 as os. Now a days, when I start the machine, all the services
of Antivirus and othen programs in the startup are showing “service failed to start”. When I tried to take the event viewer it also shows “service failed”. When I take MMC from command prompt, the same error occurs. I downloaded service pack 2 and tried to install. Then also the same error.
What will be the problem ?