Ive tried a couple of them over the last 2 years and got to say...what a waste of money.
I did not see any change in my system that freeware programs can do for you.
If you are looking for a freebie that does something similar to the winoptimizer and powerup you may like to try Winaso click here
This i have used for around 3 years and to date never had a problem.Its used on 3 pc's reguarly.
It has a trial version that is not a lot different to the full version except for repairing problems.Trial version will correct 10 errors at any one time,the full version fixes all errors.
In saying this there are plenty of free programs out there that will do this for you for absolutely nothing..just that you will need 2 3 4 programs to do this.
all these used and updated weekly will keep your pc in tip top condition.