WampServer

I installed WAMP on my machine (XP/SP3). It was running fine till I rebooted the machine. After the reboot, Apache and MySQL services are not starting. The 'Start/Resume Service', 'Stop Service' and 'Restart Service' options from system tray menu appear disabled for Apache and MySQL.
But when I execute httpd.exe manually, Apache starts. I have tried reinstalling WAMP, but faced same problem after reboot. Port 80 is not in use on my machine. I don't have IIS or Skype installed.