I don't see your point...Why could'nt he hit the damn "register" and enter his GOG key, allowing him access to everything he would have right to? (DLC) 

You know, you DID recieve a CD KEY from GoG, and it's not for the fuss. I think it's a general CD Key every other versions of the game has to enter if they want their version registered. He can just hack is way out of SecuROM + Enter the CDKey to get the DLC and all that he paid for.

Doing that would require him to run a crack to avoid the securom activation. You suggested he not run the crack, meaning he'd be stuck and unable to play the game. Obviously, if he did run the crack so as not to hit the securom that'd fix his installation issues. Whether it's legal or not, I'll let others run around with pitchforks and knives to argue about.

Thats why I never went to Windows Vista or 7...never had any problems with XP ..not with GOG, steam or anything really

I've used nothing but the direct download links for 3 years now and never had one problem.

No issues with Windows XP.

Having registration issue, but that's not on gog.com's end.
Able to play the game.

I highly doubt it's Win7. I've installed tons of GOG games on my 64 bit Win7 rig with no issues.

For all those "XP is best". Yeah. Enjoy it while it's worth it. For info, Mico$oft don't produce updates to it anymore. I mean, it's not supported, and less and less companies will support it....Not a good idea long term.

Have you tried this?:

http://www.gog.com/en/forum/the_witcher_2/use_launcher_to_activate_game/post28

people had the same problem and solved it...

I have done everything there except, uninstall and reinstall the MS C++ redistributable files from 2005, 2008, and 2010.

I guess I'll try that next, since gog tech support is no help.

Just uninstalled C++ redist package and reinstalled them. Then re-installed game with UAC and anti-virus off.

Still get the same error.

Are people still sprr\eading that ignorant BS about XP? XP was crap years ago, LMAO. WOW, people are so uninformed.

Game not Launching or "Installed game Invalid or Incomplete"? Figured it out!!!

I am using windows 7 and turning off UAC and real time protection in Microsoft security essentials before installing game (purchased from gog.com). That is not enough. YOU HAVE TO MAKE SURE THAT "MICROSOFT ANTIMALWARE SERVICE" is stopped via Control Panel -> Administrative Tools -> Services.

Run the patcher.exe (in the game directory) with this service STOPPED and the game will patch.

You can turn on Microsoft Security Essentials back on then (which will start the antimalware service).

i am using win 7 64-bit and never had to turn anything off, uac and microsoft anti-malware are both running and i had no problem d/l and installing.

also the gog key will not work on any other version other than the gog one, i know this because i tried it.

Same.

Running Windows 7 64-bit and never had to disable anything to get the game to launch.

Glad you got it to work though. :)