Need Help with Mac Install Please!!!!

I need to access a site for business that only accepts IE. I purchased a copy of Paralells (online download) and attempted to install it on my iMac. Everything was fine until it asked me to install a guest OS and somehow I got to a screen to install Vista and it asked me for the key. I am now stuck. Does it not come with Windows OS? Did I get a key for Vista? I just need to get on to the Internet through IE and nothing else fancy. PLEASE HELP..... Thank you.

 

That is an easy one. You need full version of Windows XP or Vista or anything else you want to run in Parallels. You install it in Parallels and use it in Mac like that.