Reset Internet Explorer, Mozilla Firefox and Google Chrome.

If your internet is working slower than previous, you can speedup by resetting the browser.
For Internet Explorer-
-Go to Tools
-Delete Browsing history or press Ctrl+Shift+Del on keyboard
-It will bring delete browsing history window.
-Tick mark all boxes.
-Click delete.
Done!

Google chrome
-Click right up corner "customize and control Google chrome button
OR
Press Ctrl+H
-It will open Google chrome browsing history page.
-Click "clear browsing data"
-Select "the begining of time" from up drop down menu.
-Tick mark all boxes and click "clear browsing data"
Done!

For Firfox

-At the top of the Firefox window, click the Firefox button, go over to the History menu and select Clear Recent History.
Select how much history you want to clear:
-Click the drop-down menu next to Time range to clear to choose how much of your history Firefox will clear.
-Next, click the arrow next to Details to select exactly what information will get cleared. Your choices are described in the What things are included in my history?
-Finally, click the Clear Now.

Done!