I need the advice of someone who knows about such things to help me get Windows 10. I have a two year old 17" Toshiba Satellite laptop with an 802.11n wireless card. All its drivers are up to date. I have tried on two occasions to upgrade my Windows 8.1 to Windows 10. The first installation left my computer completely unresponsive. It also cut my WiFi speed from the 100 Mb/s I pay for to one half megabit/s and I could not improve this. So I reverted to 8.1 The second installation also presented me with the ridiculously slow WiFi speed problem, in addition to corrupted data on the hard drive and corruption of my Microsoft account, which meant that the Windows 10 Mail app and OneDrive would not synchronise nor allow me to sign in. Cortana could hear me, but could not reply, going into a thinking loop every use, even though it printed what I said correctly in the text box. So I reverted to 8.1. With 8.1, there are no corruptions of data, accounts or poor WiFi speed problems, It seems that tacking 10 on top of 8.1 isn't going to work for me, even though my laptop exceeds the Microsoft specifications, isn't that old and I liked 8.1. I used the Microsoft media creation tool to download Windows 10 set up onto a USB stick. I have a usb 3 external HDD attached to my laptop and an onboard 128 GB solid state drive, on which my genuine Windows 8.1 is installed. I asked in Microsoft community if it were possible to do a clean install from the usb stick to the usb HDD attached to my laptop. They said it was. A few people say they have 8.1 and 10 on separate drives and can boot to their choice during boot up. I want to put a copy of Windows 10 onto my external HDD, so that there is no other OS on the drive and no possibility of corruption due to writing 10 onto 8.1, and change the boot set up so that it asks me which OS I wish to load during the boot up process. As I say, I really liked Windows 8.1, especially the full screen apps and the start screen. I would like to keep it for that reason and also in case Windows 10 on the external HDD goes belly-up. Another Microsoft Community user has just said that 10 must be installed onto the onboard drive, in contradiction to the MVP who said I CAN clean install 10 to the external HDD. Can anyone help me get 10 up and running without corruption of my system or it being left unusable?