I just bought a new windows 8.1 computer. I want to get GOG and my games on it. I have the games loaded on my win xp. I do not have the original install files just the games loaded to play on my system. If I copy my folders GOG from my xp to my win 8 will they transfer or do I have to do a new install of GOG and re-download all my games?

I think that should be no problem with DOS-games because they don't need any Registry-keys. But Windows-games probably won't start or have other problems.

Thanks for the quick response.. so my games are legacy of time, Pandora, Simon II, and mean streets. So I should be ok just copying over the files

Generally, I'd say that it's probably better to download them again. Windows games might have issues when they're not correctly registered with the system and games utilizing DosBox rely on Desktop/Start menu shortcuts in order to start up the necessary config file. In the latter case, you might be able to tinker with it yourself, by setting up the shortcut manually, though. Also, depending on how old your installations were, they might not have been optimized for Windows 8 yet, or have no compatibility at all. There's actually quite a few games that still have no Win8 compatibility, and some might never get it.

If you decide to re-download, definitely back-up all the installers externally. You never know what might happen...

you can redownload any of the installers from your game collection page. Its general wisdom that you should just run the installers again instead of copying over the directories (that may or may not run depending on the game).

Well, if this is the account you bought those games with, they should still be in your library, as you can download them as many times as you like.

However, I can tell you that at least Simon the Sorcerer 2 is supported by , meaning that you can very easily take the [url=http://wiki.scummvm.org/index.php/Datafiles#Simon_the_Sorcerer_II:_The_Lion.2C_the_Wizard_and_the_Wardrobe]game files from the GOG installation, put them into your own directory and then add it to your own installation of ScummVM.
With the other games, it's probably too cumbersome to really bother with it beyond just downloading them.