|Yea , I also think its in the PC , not the Internet connection.|
You can take a speed test, but your PC files are your most likely culprit.
If you don't have the tools to help optimize & clean the system , try to download & install these "FREE" utilities.
When using Glary utilities, Don't use anything under In "Privacy & Security" until you read things carefully. You can delete something forever very easy.
http://www.avast.com/en-us/index will run out in 30 days unless you register it "For Free" ( use any name & email)
As Curt R said, Malwarebytes is good , but I have it & I haven't found anything that Avast hasn't found first
I primarily use Auslogics Bootspeed & Avast.
15 day trial Auslogics Bootspeed
( make sure to UNCHECK any programs that may try to install with it, if there is any , like a tool bar or browser)