Here are a number of things which can interfere with your Windows 10 upgrade, which have happened to me.
1) hardware issue – video card loose in its slot. I would like to blame the earthquakes but more likely I didn’t push down hard enough when I installed it.
I never said hardware was my thing.
2) WiMo internet switch device may be interfering with home Wifi. This was a timer ehich I use to contol lights over the net.
3) Windows install from USB does not like you to have a DVD in your drive at the same time, it confuses it.
4) (warning geek speak) Bios settings were a bit strange. These are the settings your device uses to start up and load windows. For some reason, default settings were set up for a networked environment with central control of operating system updates. I have one PC.
5) as a result of previous failed attempt to install, Windows 7 install was a recovery install which seemed to have some issues. Explorer kept crashing, but this may have been due to the DVD in the drive.
6) original usb stick I was using to create install media was too small and Windows did not correctly report this. My error message just said “Something happened” which wasn’t really a helpful troubleshooter.
7) “If anything can go wrong it will” – Murphy’s Law. Murphy must have been a computer tech.
8) Never believe you are silly to ask for help. Always feel free to talk to someone. I am a geek (but not a hardware expert). I love technology. It would have taken me forever to identify all these issues alone though. I had a friend with me while sorting this out and two heads were definitely better than one! Also if anything seems unusual, google it! It nay have happened to someone else.
All now under control and I am a happy user of Win 10. I’ve not done any formal speed tests but it feels much faster. Maybe I’m crazy but am going to do the old laptop. Don’t let me scare you. Many friends have not encountered any issues at all and even if you do, it is worth it in the end. Just back up your files and settings first. I didn’t lose any data, despite the rocky road I travelled but there’s never any promises.