Some problems

Hi, Ive got the latest version of WP. And Ive got some problems…different areas:

1. I installed WP via simplescripts on my host. I gave it a name. Now the project has changed and Im using the same install for another project. How can I change the name?

2.Is there any way of achieving a sticky post? do you have to use plugins?

3. Im using a theme that assigns a thumb nail image to the category. So all posts inside that category have the same thumbnail image. Id like to assign different thumbnail images to all posts.

Thats it for now, please help me out if you can!