My laptop runs soooo slowly. I know I have useless files but I don't know how
to clean them up.
Useless files have no effect on the speed of the computer, and are not
your problem. If some of those useless files are program files, and
those programs are *running*, they may have an effect on speed.
Cleaning up useless files may be good to do to save disk space, but
look elsewhere for your performance problem.
Can someone help with this?
It's very difficult to help you, since you've provided essentially no
information. Start by answering the following questions:
1. What is your hardware configuration? CPU, amount of RAM?
2. What firewall, anti-virus, and anti-spyware programs do you run?
Are they kept up to date?
3. What programs to you have automatically starting with Windows?
(Look in MSCONFIG to see these.)