I'm working with a computer with Windows 7 Ultimate and I'm trying to open a pdf document but when I'm trying to open it, says that the application couldn't start correctly.
As you mentioned you are getting error 0xc000000a5 error when tying to open pdf, please try following troubleshooting steps:
1- Check if an update is available for Acrobat using "Check for updates" option under "Help" menu, reboot the machine after installing update and try again. You may also download updates from here: Adobe software and product updates
2- If that doesn't work, locate Acrobat / Reader shortcut>Right click>Properties>Compatibility tab> check if its running in compatibility mode, if it is, uncheck compatibility mode and try again.