After upgrading to Maverick, my computer constantly loses internet connectivity

Question

I have an iMac with 3.06 GHz Intel Core 2 Duo processor, Memory: 4 GB 1067 MHz DDR3, 1 TB storage capacity.  Since upgrading to Maverick, my internet seems to lose connectivity constantly.  Almost every time I open up Safari and type in a search, I get an error message that I am not connected.  All I do is just press the Enter button a couple times, and it connects and opens up a web page.  If I am watching a long video (20 minutes long), the internet will almost always cut out during the video, and I just have to click on the bar at the bottom of the video to get it going again. 

Answer 1

Please answer as many of the following questions as you can. You may already have answered some of them. In that case, there's no need to repeat the answers.
Have you restarted your router and your broadband device (if they're separate) since you first noticed the problem? If not, do that now and see whether there's any change.
If your browser is Safari, then from the Safari menu bar, select
          Safari ▹ Preferences... ▹ Privacy ▹ Remove All Website Data
and confirm. Any change?
Quit and relaunch the browser. Any change?
Are any other web browsers installed, and are they the same? What about other Internet applications, such as iTunes and the App Store?
If other browsers and Internet applications are also affected, follow these instructions and test. Any change?
If Parental Controls is active for any user, please turn it off and test. Any change?
Are there any other devices on the same network that can browse the Web, and are they affected?
If you connect to your router with Wi-Fi and you can also connect with Ethernet, do that and turn off Wi-Fi. Any difference?