Hi Alex,
Did you plug a pc-remote cable to your remote control RJ11 socket?
Are you using Celestron Unified (5.0.10) driver from ascom website
http://ascom-standards.org/Downloads/ScopeDrivers.htm
I used to have a similar model 4 SE( which i guess just a special edition and comes in orange) and never had any problems connecting to PC via ASCOM.
You can also try to connect to NexStar remote software(should come with a scope) just to check that you are using a correct COM port number in software settings and your PC-remote cable and a socket on your remote work. As far as I can remember Nexstar software does not use ASCOM and only asks for com port number.
cheers,
Mike