How do you reset a Sony blu ray surround sound bdv-e3100 after a power surge

First of all be aware of the official warning that region code can be changed ONLY 5 TIMES.
And last choice region becomes PERMANENT.
Read here:
https://us.en.kb.sony.com/app/answers/detail/a_id/41348/p/46871%2C74232%2C74609/c/65%2C66/kw/region%20code

Your device manual:
https://docs.sony.com/release/BDVE6100_E4100_E3100_E2100.pdf
Test this:
How to Change the Region Code on DVD for Sony Blu ray Techwalla com

What you mean?

Not all Hdmi cables have same capabilities. Check out:
http://www.hdmi.org/consumer/finding_right_cable.aspx

How have.you connected the TV to the surround unit ?

try this
1. Press DVD
2. Hold the magic button until the DVD button flashes twice.
3. Press 0533

4. Hold the magic button until the DVD button flashes twice.
5. Press 994
6. Press Magic Key (don't hold)
7. Press 1891 (this sets key 1 - the DVD button flashes twice)

8. Hold the magic button until the DVD button flashes twice.
9. Press 994
10. Press Magic Key (don't hold)
11. Press 2552 (this sets key 2 - the DVD button flashes twice)

12. Hold the magic button until the DVD button flashes twice.
13. Press 994
14. Press Magic Key (don't hold)
15. Press 0953 (this sets key 3 - the DVD button flashes twice)

16. Hold the magic button until the DVD button flashes twice.
17. Press 994
18. Press Magic Key (don't hold)
19. Press 2214 (this sets key 4 - the DVD button flashes twice)

20. Hold the magic button until the DVD button flashes twice. .
21. Press 994
22. Press Magic Key (don't hold)
23. Press 0795 (this sets key 5 - the DVD button flashes twice)
Done - the remote is now programmed and ready to use

There have been problems with firmware updates, go online to Sony and contact customer support and the technical department for answers. It is pointless when you must reset the processor constantly

It's already Region Free when purchased.

A+B+C Multi Zone Region Code Free Blu Ray Player DVD Region 123456 PAL/NTSC

PAL or MULTI-SYSTEM TV is required to watch PAL DVDs. If your TV was purchased in North America (NTSC) you will also need a Video Scaler Full HD 1080p.

they had thier own support network

I found some support for a SONY BDV-360FS on their european site.
This is the closest model # I could find.
Is this the unit you are looking for support on?

Not the BDP-S300 or BDP-S350 blu-ray players, but a player with a builtin amplifier and speakers, is that right?

Hello, it sounds to me like the receiver doesn't support the sound format being sent from the blu-ray player. This is because the blu-ray disc would have HD encoded sound such as DTS HD Master Audio or Dolby True HD. Most receivers have not been fitted with these sound formats untill quite recently. The reason for the menu sound playing correctly would be for the PCM (Pulse-code Modulation) which sends simple two channel digital sound supported by all digital receivers. It may be possible to use Dolby Pro Logic or similar formats to give a surround feel, but the only way to get true surround sound in this way would be decode the sound externally and input it through several phono cables into the multichannel input, however blu-ray sound comes in 7.1 so the receiver would need to be able to accept this to get the full effect. If it is possible, see if the blu-ray player will allow downsampling to a surround sound format that your receiver can accept such as Dolby Digital or DTS. Hope this helps.