my computer is being wonky

[Zivon23]

ok...I have 2 issues.

First, it is a used computer that has 2 copiies of windows on it.  1 is one the C: the other is on the H:  When boot the computer up, it gives me a choice of which windows I want to use.  How do I get rid of this?

Second,  The computer only has 1 desktop and was logging strait to windows when you booted up.  Now for reasons unknown, it doesn't go directly to windows....it goes to the log on screen(as if there was multiple desktops).

I am running windows XP Pro with SP2.

Thanks in advanced

~Z23~