It's not his install of Windows that is bad, or his hardware, or anything like that. I get this issue too on a clean install of Windows 10. It's one of the drivers that has gone bad and causes freezing, particularly when the GPU is being used, like when playing a game (whole computer freezes) or when watching flash video the tab will freeze and eventually the whole browser will freeze, even with Hardware Acceleration off.
My suggestion is to just use all default drivers except for the latest Intel chipset driver, and wait for newer drivers that won't cause freezing.
I may go through and manually check every driver and see which one is the culprit. My money is on Intel RST, I've had freezing happen before because of it.
Edit: I downloaded the latest ethernet drive from here:
http://www.intel.com/support/network/sb/cs-006120.htm and latest RST from here:
https://downloadcenter.intel.com/download/25165/Intel-Rapid-Storage-Technology-Intel-RST-RAID-Driver and both seem stable so far.
Edit2: I installed ASMedia USB and AHCI drivers, everything is still fine.
Edit3: It wasn't RST or the Ethernet driver, it was the Wireless/Wi-Fi driver. No wonder why they call it a beta. Install any driver you want, just don't install the Wireless/Wi-Fi driver.
Edit4: It's still happening, it has to be one of the other drives. For now, only the Intel chipset driver is safe.
Edit5: After more testing, I have confirmed once and for all that it is the ASMedia USB drivers that cause the freezing. Everything else is okay.