Did you check if the drivers are still in place? I have had more than one instance where they just dissapear and you pc can no longer read flash drives.

Some references I found from a quick Google search:

1. http://www.tomshardware.com/answers/id-1751461/mouse-keyboard-work-bios-wont-work-windows.html
A) "Use the standard USB 1.1/2.0 ports instead of the USB 3.0 ports, which are attached to 3rd party chips, for your input devices."

B]

 

 

2. http://www.tomshardware.com/answers/id-2284618/usb-ports-working-work-bios-asus-z97m.html

 

 

3. https://www.drivereasy.com/knowledge/fix-issue-after-upgrade-system-to-windows-10-usb-ports-dont-work/
A) Check if the problem is caused by power supply issue.

B] The Power Management would also be the cause of the USB problems. (need a working mouse/keyboard)

C) Go to Device Manager to check for the driver status. (need a working mouse/keyboard)

See the links for more extensive details/instructions. Sorry I can't help more beyond simply googling, I have no experience with the problem.
Here is the search phrase I used: https://www.google.com/search?q=usb+devices+not+working+after+bios 

Thanks for your help. I will try the proposals you gave me.

I do not understand. I tried everything ... Can not try other devices. I do not have other computers to help me.

 

I do not know if this can help but here is my setup.

 

I7 6850k

Asus strix x99 gaming

Strix gtx 1080 SLI

Corsair dominator 3000mhz?

Be quiet! Power Dark pro 1000W

 

If I format, can I simply format the hard disk "c"?

 

thank you,

Hello! I would recommend you ask a friend or a computer technician to help you with troubleshooting the issue first. 

You could also attempt more solutions from Google, but searching will be a bit difficult if you are doing it with a mobile phone.

As a last resort, which I really hope you can avoid having to do, I *think* reformatting can simply be done on your root drive with Windows installed. Usually that is your C:. However, if you have partitions of the same drive, those will probably be affected as well.

Hopefully some one more well versed can give you input on the matter as well! It would be really helpful if you could get some help to look at it physically on your end.

What windows version do you have?

 

You haven't need to format "с". If you have encrypted files on other disks, they can be unavailable due to NTFS features.

 

All what you need is boot from your  windows install or recovery disks (DVD or flash). Depends on what you have. Then you can recovery system on install it above old one.

 

Also you can try to boot windows in safe mode (use the F8 key when the computer boots up.  that  trick doesn’t work for all Windows 8 PCs.)

 

Next you would delete usb drivers by windows device manager. Then reboot to normal mode.

> did you try the secured modus, with only basic drivers? Something seems to interfer with the interface devices within windows

> did you try to swtich USB ports? Maybe you got some low-tec USB ports (what is it, there are 3 generations now?) of the first generation. Slower, but fast enough for mouse and keyboard

> is a cable on the mainboard not where it is suppsed to be? Did you try to replug everything, exterior and interior?

 

If all fails, and before you format your PC, best take it (or the HDD / SSD) to someone who can plug it into his / her PC and copy all data, like from an exterior hardrive. No data loss that way.

I'm late again. Darn, and I love fixing computers too. If you still want to figure out why that problem happened where you couldn't log in, I could help track it down.

 

As for the background service "svchost," is it taking ALL your bandwidth? If it is on/off I wouldn't worry, windows checks for updates and does small things without bothering the user. But if it is a real bother and won't stop, try to find "Transfert intelligent en arrière-plan" and "Mise à jour de Windows" since your windows is in French. But as a computer geek I say don't disable these services unless you are sure, windows update is very important. If you still want to disable and want me to help, you can PM me.

A strange program takes all my bandwidth ... "svchost netsvcs" ...

 

I tried that.

svchost.exe is a process your system uses to host other services (mostly related to web connections in my case). So most of the time it is used by the system when he is busy doing something, after a program has been launched for example. It's not a virus, though if one of your programs is stuck doing something it can effectively consume most of your system's ressources..

 

However there are A LOT of virus who uses names close to system ones, so that the user gets confused in thinking the process is for the system.

So if the process isn't exactly named svchost.exe, but something a bit different (with a letter, or a space added) then you can start looking for viruses or doing online scans (with kaspersky for example).

You've activated the automated update service for your windows?

 

I run only Win 8.1 but had the same problem (It's a common problem.). When you set it to "check for updates but don't install it", this update service causes high CPU load. It's more like "I want to update but i can't... but i try it, try it, try it, try it..." >>> voila, the service runs over and over and over a long time without any results.

 

Set it to search and install updates complete manually (it deactivates this service, should work for Win10 too). 

Try it and check it. Change this your problem or not?

 

With high bandwith you meant your CPU load, right?

 

netsvcs is tied directly to the windows update service.