I am just loading up a new Windows 7 workstation PC, and I'm installing the software applications I need, one-at-a-time. I needed Adobe Reader — a free download from Adobe. I installed it, and — to my surprise — found out that I had also inadvertently installed McAfee Security Scan Plus. Now, first-of-all, I already have an anti-virus solution. Second-of-all, isn't a program like McAfee Anti-Virus supposed to help you prevent loading stuff on your computer that you don't want?
When we help clients with their computer network environments, we notice that sometimes they have multiple (unnecessary / redundant) pieces of software on their machines. If you have two species of anti-virus software running, they can conflict with each other and cause problems. If you have so many toolbars on your Internet Explorer Browser that you can hardley see the working area of your screen — do you think that might slow down your machine a little bit?
As a first-line-of-defense, just be careful when you install new software, that some other piece is not piggy-backing along with the install. Secondly, if you realize you installed something you don't need, go to add remove programs, and uninstall it.