too many styles

I am working in Word 2003 in a large document, and I assigned styles for Headings (for the TOC) and for text blocks. I turned off the “auto-Update” box (or so I thought: Word still seems to change fonts, margins etc…), and I assigned my names to the styles, so I will know what to use.
1st problem – assigning names.
2nd problem – CAN YOU ERRASE STYLES FROM THE LIST?
3rd: can you make a short list to be used in one doc, and get rid of the rest of endless Word Styles, or call on only certain ones (I needed “Captions – but cannot make it stay centered…)?
THANKS!