How do I go back in time?

How do I go back in time?

If you're referring to Time Machine, you have to set it up first. Did you do that?

I downloaded something and I can't get rid of it.

What might that be?

Also, is there a virus/spam remover program that is good on a mac?

Anti-virus software is not needed unless you want to be able to detect Windows malware (which can't affect your Mac, unless you run Windows on it.) In that case, use ClamXav -- nothing else.

The built-in Mail application has spam filtering, if you find that useful.

Mail > Preferences > Junk Mail > Enable junk mail filtering

You don't need TM for this. (Although some kind of backup like TM or a bootable clone is a must.) See this thread with some possible solutions.

https://discussions.apple.com/thread/2179391?start=0&tstart=0

Now every time I sign in I get a pop up that says safari cannot support a community toolbar.

how to get rid of the safari community...: Apple Support Communities

Is there a tute on time machine so I can set it up?

Mac 101: Time Machine

For Time Machine, see Pondini's articles;

http://web.me.com/pondini/Time_Machine/Home.html