Free ware problem and antivirus protection

Sorry if this isn't the right board to post this, and I'm sure this has been asked a lot... but I'm on a new computer and a Firedog advertisment keeps poping up randomly, sometimes every couple of mins. I tried to stop the loop in the file menu when it pops up, but that doesn't work. It is like some advertisment for a antivirus. I plan on getting one as soon as possible but I just want to stop this from poping up right now.

In addition, there is probably lots of stuff I want to get rid of that has been put on this computer. I was thinking about buying the best antivirus software that I can afford when I get some money. Would it be a good idea to take the computer to where I buy the antivirus software and have them install it, as well as install Microsft Office and delete all of my free ware? Should I just buy the antivirus software and do the rest my self? What kind of antivirus software should I get with a cable modem? I've installed stuff before, I just want to be cautious.

Sorry if this isn't the right board to post this, and I'm sure this has been asked a lot... but I'm on a new computer and a Firedog advertisment keeps poping up randomly, sometimes every couple of mins. I tried to stop the loop in the file menu when it pops up, but that doesn't work. It is like some advertisment for a antivirus. I plan on getting one as soon as possible but I just want to stop this from poping up right now.

In addition, there is probably lots of stuff I want to get rid of that has been put on this computer. I was thinking about buying the best that I can afford when I get some money. Would it be a good idea to take the computer to where I buy the antivirus software and have them install it, as well as install Microsft Office and delete all of my free ware? Should I just buy the antivirus software and do the rest my self? What kind of antivirus software should I get with a cable modem? I've installed stuff before, I just want to be cautious.

AmidstTheLight

To get rid of unwanted programs, Click Start -> Control Panel -> Add/Remove Programs then just remove all the ones you don't want.

For anti-virus protection you can download a free program that works just as good as a retail one if not way better. I suggest searching google for AVG Free. It's a pretty decent anti-virus system and it doesn't use much system resources.