The program if its the legit one is legit however follow Spence advice, and don't do it. Especially if you dont know what you are doing, if you want a good speed up program AVG a very trusted source has a great one, but regardless if the PC is not cleaned and in good working order prior it will not matter, it will clean cookies, and defrag and shut down un wanted services, making it appear much better for a little bit then WHAMO!
A lot of Malware mask themselfs as legit software,
here is the website of the one you are refering to. But again, if you don't know what you are do, don't let it scan, get it removed from your pc by someone that knows what they are doing.
Most tweeters are installing this with out knowing it, at least that is what my research is showing.
Edit:
I just saw the Kindle and Ipad comment, please just return the PC, us microsofters thank you.