The very first thing you need to be sure of is that your internet connection is delivering the right speed and in our arsenal is a connection speed test to test that your internet connection is delivering what you are paying for. The cheapest ADSL package is not always the best package to go for.
First off take the Broadband speed test to see your upload and download speed.
Next in the productivity arsenal is to do a full system scan using your antivirus software. Avast is free
Then you will want to clear your browser cache, be careful not to clear any saved passwords.
Next in your arsenal is to check that you do not have any programs installed that you tried but never used and remove them to free up disk space.