Install window services

Are you using try/catch blocks to handle exceptions?  That's important in any application, but especially in a service because there's no UI to report errors with.  You should write Event Log entries for any caught exceptions, making sure to include any inner exceptions and their messages and stack traces.  This will be a big help in diagnosing any failures.

Also, try running the service under a different user account (double-click on service, go to "Log On" tab, change to "This Account" and specify an account that has the proper permissions to access whatever resources that the service needs to function).