Internet and Taskbar Stop Working

Hey, guys! While I'm new to this forum, I'd like to consider myself tech-saavy (I'm an assistant web developer); however, when it comes to operating systems and troubleshooting things, I seem to be at a loss.

Here's a typical day for me:
1. Turn on my five-year-old Dell laptop.
2. Wait a few minutes for everything to start working.
3. Either access Firefox, OR go to the Windows internet connection manager and hit "Repair," because it's showing the yellow "!" symbol. After I "repair" the connection, I can access Firefox.
4. After browsing the internet for anywhere between a few minutes to several hours, websites stop loading.
5. I go to the taskbar, click on the Windows internet connection manager, and nothing happens.
6. I go to the Start Menu, try to access the internet connection manager from there, and either nothing happens, or the whole taskbar freezes (including the Start Menu).
7. Since I can't even shut down my computer via the Start Menu at this point, I have to force a shut down, and repeat the whole cycle over again.

I am at a loss on how to even begin solving this problem, as I'm not sure where the problem is coming from! Thank you in advance for your help. :)