I've looked at the technical faq, but I am unable to find the file to edit these settings:

1. Try turning off movies in the user.setting by changing ShowIntroMovies TRUE to ShowIntroMovies FALSE.
2. Try manually changing the resolution of the game in user.setting by changing the values associated with WINDOWEDWIDTH and WINDOWEDHEIGHT.
3. Try manually changing the MULTISAMPLETYPE setting to a value between 0 and 4 in the user.setting file.
4. Try updating your sound card drivers to their latest version (this is especially important on brand new machines).
5. Make sure you video drivers are up to date.
6. Make sure you have the latest DirectX 9c.
7. Try manually reducing all your texture levels in user.setting (set them to 0 for the lowest setting).
8. Try updating to the latest version of Sins using Stardock Central.
9. Try running in windowed mode (ISWINDOWED FALSE to TRUE) also set in user.setting.
10. Try reinstalling Sins (make sure you uninstall and manually delete anything that might have been left over)
11. Try changing the game resolution to the same resolution as your desktop.

Where is this User.setting? I can only find Userinterfaceoptions, and there isn't a settings folder in my documents, since this is a clean install and I've not yet started the program succesfully.

Another thing of note, it never asked for my serial key while installing

Edit: Found them. Took a little digging, since there was no Appdata folder directly under User that I could see, but it was there.