I've been trying to solve a issue with Youtube video's crashing my internet connection for a few months, and finally figured out what the problem was. I run AVG virus scanner - the paid version, not the freebee - which has a built in Video Accelerator. Apparently Youtube doesn't like this. Disabled it as follows and Youtube problem went away.
You can disable it in AVG Tools -> Web Browseing Protection-> Online Shield -> untick "Enable AVG Accelerator".
This is your destination in the 2013 version of AVG. I don't know for sure, but the same or similar problems may occur with other video accelerators, so if you're having this problem try disabling or removing the accelerator.
You can disable it in AVG Tools -> Web Browseing Protection-> Online Shield -> untick "Enable AVG Accelerator".
This is your destination in the 2013 version of AVG. I don't know for sure, but the same or similar problems may occur with other video accelerators, so if you're having this problem try disabling or removing the accelerator.