Let's tackle the mouse and keyboard issues as we can't assume anything at this point
Are both of them USB connected?
Are you sure that both of them work ok on another computer?
--- I know that sounds like a foolish question but even the simplest item needs to be verified
Is the mouse battery operated? If so change the battery
Then there's the Internet connection
--- Personally I recommend hard wired Internet connection from start to finish
Bottom line: don't trust anything wireless (mouse or Internet) at this time
--- It's not that it can't be done that way but in a situation like this it's back to the basics even if it isn't known why
EDIT: The only items that should be connected to the computer are the Ethernet cable, keyboard, mouse and monitor: nothing else. If there is a ireless item such as a wireless printer, shut it off.
On the black screen, try another good known working monitor especially one that does work on someone's Windows 10 computer if possible
If somehow the above ideas can come together "ok" post back using another computer and let us know what's happening.
Personally it appears to me you should revert back to your Windows 7 on the first chance you get
--- Verify everything in Windows 7 is up-to-date and security is clean
--- Follow Niweg's recommendation: create a system image backup of Windows 7
--- I'm with Niweg 100% on that
--- Before you are ready to try upgrading to Windows 10 again, completely disable or uninstall AVG whatever you have
Please let us know why you used a Windows 10 ISO and instead of the Get Windows 10 icon in the lower right corner of the taskbar
Are there any other factors we need to know?
--- Such as is this the first time you tried upgrading to Windows 10?
Here is another "stretch"
--- Can you get a system repair disc for your Windows 7?
--- It might be helpful if you can try to do a system restore
Back to the keyboard, mouse and monitor issues: if each one proves to work on a another computer hard wired, when you boot your system back up give the computer plenty of time to completely boot up
--- I've seen a few cases where it took about 30 minutes to do so
There's more to be said, but it's difficult to cover all the bases at this time
Edited by cmptrgy, 23 March 2016 - 03:13 PM.