Hello again Lilia,
I would recommend not using tuneup utilities just because windows 7 is already streamlined, already set performance wise. While the choice is yours, there really is no need for such a program, and there is always the possiblity that such programs increase the risk creating more problems than they actually solve. This is the same for registry editors. If you are worried about speed, see the optimization link in my signature. Unless you know exactly what these programs alter when they do their 'performance enhancements', and are alright with it, I would stay away from them.