Solved Windows 8 theme changes at startup

I used the netplwiz option to disable password at PC startup. After a while, I changed my windows colour from purple to blue. Now, every time I start my PC, the theme changes from purple to blue, while the "welcome" screen is on.
I tried changing the colour, but same thing happens: for a second, while the "welcome" screen is on, the theme is purple, then it changes to the theme that i selected.

Why is this happening, and how cand i solve this problem?

Hello Pat, and welcome to Eight Forums.

In Windows 8, there is two different backgrounds for the sign in screen. One is the default background that displays when either no or all users are showing on the sign in screen, and the other is the user specified background that displays when only that user is showing on the sign in screen.

On the "Welcome" screen, you would see the default background briefly at first, then the user specified one as the user account is being signed in to.

Since you have Windows 8.1, you could use the tutorial below to specify a default background color for all users so it will be the same if you like.
Hope this helps,
Shawn

The registry hack worked! Thanks so much! I've been looking for a solution for a long time!

You're most welcome.