I need to know if this will work

Ok so the 1st time i used it.... everything looked ugly and no themes worked so now i read some more today and i have found out that im a service pack 3 so i went back to the help section and down to the bottem and gave me a link i clicked on it and it took me to a website which gave me a program called "UXTender" and it said it was for service pack 2 and 3. Im hoping that this wont wreck my comp again and i would like other people with service pack 2 or 3 to just confirm that this is safe? thank you.