In need of free window-washer type program, 7 yr old son downloads nick games--

I NEED HELP FINDING A GOOD, TRUSTWORTHY, FREE PROGRAM TO WASH MY COMPUTER AS THE INFAMOUS WEBROOT WINDOW WASHER DOES (FREE TRIALS HAVE EXPIRED) AS MY 7 YR OLD AUTISTIC SON DOWNLOADS ALL THE NICK GAMES HE CAN DOWNLOAD, IS DRIVING ME CRAZY AS MY WINDOWS XP PRO REALLY SLOWS DOWN TO A CRAWL, CAN ANYONE HELP PLEASE?????

Please download the current version of HijackThis from HERE

• Double click and run the installer.
  
• It will install to C:\Program Files\Trend Micro\HijackThis\hijackthis.exe
  
• After installing, you should get the user agreement, press accept and Hijack This will run.
  
• Select Do a system scan and save a log file. This will open a notepad file of everything Hijack This found, copy and paste it back here.