slow speed and crashing

i just got my laptop used and it has a bunch of programs and things that idk if i can delete or if the need to be on here it seems to be really slow when im surfing the internet and it will just randomly crash on me if someone could help i would greatly appreciate it.

the only thing i have done so far is used ccleaner and i have also deleted some programs like frostwire and things like that.

First
lets run and antivirus scan

Then download and scan with malwarebytes.
http://www.malwarebytes.org/mbam.php