SPYWARE software question

i am beginning to get pop-ups on my computer. my nephew downloaded a software program called WINDOWS LIVE ONECARE onto my computer. and to get rid of the pop-ups someone suggested a free SPYBOT download. here is the link.

http://www.safer-networking.org/en/home/index.html

i know nothing about computers and can not understand computer language. i read something once that said something about the computer messing up if you had more than one antivirus program. if i download spybot will it cause problems with windows live onecare? thanks. barb