Hi, So a couple of weeks ago I brought all three Rollercoaster Tycoon games from GOG and they played fine. Lately I've just been playing the third one and today I wanted to play the first one so I clicked on it and nothing happens, I'm also having the same problem with the second one. Help?

On Windows 7 (may or may not apply to other versions of Windows) you need to add the games to your Data Execution Prevention list: Control Panel > System and Security > System > Advanced System Settings > Advanced Tab > Performance Settings > Data Execution Prevention Tab > Add button > navigate to the install folder, select RCT.exe and click Open.

I've added both of them to DEP and restarted the laptop but they still won't start, I click on them and I get the blue spinning circle for a second and then it goes back to the normal cursor and the games won't start.

Hi !
1) Did you tried to launch one of them as administrator ? (right click on the shortcut -> run as administrator)
2) Can't it be an antivirus trouble ? I have Avast and it made me this kind of troubles sometimes with some softwares (but not gog games) until I disable a new functionnality introduced in an update
3) What graphic card do you have ? If it's an ATI, have you make an update ? (because they aren't always advised for old games)

My laptop has a NVIDIA GeForce GT 750M. I've tried updating my Graphics card drivers and adding the two games to the Data Execution Prevention and now RCT 2 works fine but RCT 1 still won't start.

Strange that the 2 works and not the first...

Someone seems to have the same problem (RCT1 who didn't launch properly), but they have solutions to try : http://www.gog.com/forum/rollercoaster_tycoon_series/rollercoaster_tycoon_doesnt_start/post2

Go take a look ther :) Hope it will helps you, and that you'll get it work again ! ;)