I do IT support for a law firm and I have a few clients with Surface Pro 3 and 4. The following steps work on the three occasions I've seen the frozen screen issue. Do not use these steps with RT or non-pro models:
Step 1:
Press and hold the power button on your Surface for 30 seconds and then release it.
Step 2:
Press and hold the volume-up button and the power button at the same time for at least 15 seconds, and then release both.
The screen may flash the Surface logo but continue holding the buttons down for at least 15 seconds.
Step 3:
After you release the buttons, wait 10 seconds.
Press and release the power button to turn your Surface back on.
On only one other occasion did I have to resort to the boot usb (which I got from support in the Microsoft store.) If there is a store near you, take a usb and ask them to give you a copy of their boot usb and instructions to use it. It really is handy when your Surface boots but goes to an error screen.
General comment:
I've been using Surface since they first came out. Any laptop/pc/tablet may exhibit problems from time to time. It has more to do with the components (built in different countries) or an update vs. how long you've owned it. I've had HP PCs fail after a week because of a component came from a defective lot.
Surface is an excellent product and I doubt I'll ever use anything else. It has proven to be an asset for productivity in an enterprise environment. After 30 years in technology I know to expect the occasional defect or update snafu and you work to correct it. This happens to Apple, HP and Dell and Sony. I've seen it happen less with Asus or Lenovo but it does happen. Invest in the extended warranty if the model you purchase warrants the additional expense.
Hope this helps.