Quick good and free.
http://www.savemybutt.com
Their weekly fab five is more than you need to keep a computer running 
smoothly.
1.  Advanced windows care.  This will do the most good and is very easy to 
run.
2.  spybot search and distroy.  Install and use the spybot search for blind 
operators option.
3.  ccleaner, disk cleanup on sterroids.
4.  malware bytes anti-malware.  takes a while but is thorough.
5.  revo uninstaller, right click, arrow down once, and follow the dialog. 
Take the default settings.  This is more thorough than the add remove from 
with in windows.  Free programs are not free, because somebody has to pay 
the freight.  The freight is often toolbars, from different companies.  They 
don't help us and can cause unknown problems in your web browzer.
Uninstall bing, ask.com, google, and yahoo tool bars. n  They are hidden in 
the instalation of various and changing programs.
You might also see a very evil thing called bonjer, uninstall that to.