Most likely, you're saving the CSS just fine. If you'd like it to open in IE you can change the file association. See http://articles.techrepublic.com.com/5100-10878_11-6172036.html for how to do this. Note, though, that there's no real purpose to opening a CSS file directly in the browser. It's meant to be loaded automatically from an HTML file using link rel (See http://htmlhelp.com/reference/html40/head/link.html ).
Update:
"I changed ".css" to open in internet explorer as a default program, but now a window keeps popping up saying "do you want to open or save this file?""
Yeah, I didn't realize that would happen (I thought it would display as text), but like I said, there's no reason to open CSS directly in the browser.
"I don't understand how i will be able to view how my css coding is going if i can't keep checking back with how it appears in internet explorer...what can i do?"
You check back by opening a *HTML* file that /includes/ the CSS file (you don't need to open a new instance of IE; just push Ctrl-F5). See the link rel I gave, if you don't know how to include CSS.
"I'm only using Notepad becasue it's what i used last year when doing html...what other program can i use?"
There are lots of choices, including emacs, vim, Notepad2, Front Page, Dreamweaver... It depends how much you want to do, and how much you want the program to (try) to do for you. Keep in mind the program isn't always right...
"If i used my laptop (which doesn't have Vista) would that be better?"
Not necessary.