You can go to the Control Panel and find User accounts and then select to Remove Your password.
However if you have the screen saver set to "butt in" every few minutes you will still get that, even if you remove your password, so you need to set the screen saver (assuming that is what is butting in) and remove the time currently set for it to butt in.
p.s. If this is Windows 8 the instructions above may differ slightly, I have only used W8 briefly and I am currently using w7.