Setup for Duke3D will not start on my system :( I run it as administrator, 6 GB of ram.
When I click it, I get the windows hour glass for a microsecond, the nothing. Nothing in the task bar, nothing in the task manager, no process in processes.
I've tried to set it in compatibility mode to XP and anything below, but no luck. It won't start.

The installer won't start, is that it ?
Any chance your AV is getting in the way ?

Well, yes, gotta have antivirus :P
Got AVG 9.0 running. I'll see if I can get it shut down...

Yes, we gotta have them ;)
Don't forget to re-enable AVG once you're done testing the issue.

I will
I do however see that the Descent 3 + Exp.pack won't start either, but when attempting to start that results in an error message. Not much help in that though, the usual "has encountered a problem and needs to close." message.
Will try to start in safemode, see if that helps.
EDIT: It might also be a corrupted download. I redownloaded the Duke3D setup, and now it gives an error message of corrupted setup files. I'll try again without the downloader! :)
EDIT2: Yep, currupted download with the downloader. Downloading from browser goes well, it's installed now :) I won't use the downloader again :P
EDIT3: And playing!! :D Problem solved!

Thank you, glad to be here. I'll be browsing this site frequently, seeing that blizzard opens up their vault of classics. (right?)

Well, lots of people around here seem to think there's a good chance they will now. I hope so ;)
You can sign up for receiving gog's emails for promos and new releases. You can do that from your 'My account page', on the ''Account and Settings' tab. Good way to keep track of new releases. And gog does great promos, don't want to miss those ;)

eh, eh, well, actually Lost Vikings was mentioned a few times in this thread, so i think you're not the only one.
Have fun ;)