This is a summary of the 9 hours spent on installing Windows 10 Pro upgrade with a USB boot and install, to acquaint myself with the new features.
The installation was on a 32 bit desktop with 2 GB DDR2 of RAM, with an Intel Duo processor @ 2.4 GHz, a standard BIOS, and a registered copy of Windows 7 Pro.
Downloaded the ISO, rather than wait for their notification (I qualified).
Got my Windows 7 product key on hand to install Windows 10.
Learned that the file system of the USB depends on the boot type.
a.) If it's a BIOS or a hybrid BIOS & UEFI boot system. This requires the USB key to be formatted as NTFS !
b.) If it's UEFI or GPT boot system, it requires the USB to be formatted as FAT32 ! - This is not a mistake, just strange.
After formatting the USB to NTFS, I used RUFUS USB creator to copy the ISO to the USB. (UnetBootin didn't work for me).
I left the C: drive (80 GB) as is, with Windows 7 installed, rather than reformatting the drive. There is no data stored on the C: drive. The installation moved Windows 7 a folder named Windows.old. This was for restoring the old system.
At the start of the install, it requested my product key and rejected it.
At this point I decided to abort the installation and selected to revert to the previous OS, but another MS miracle it ignored my command and proceeded with the install.
The OS installation insists on using the email account, username, and password of any Microsoft services, like Live, Hotmail, Outlook, or Skype to be the login and password of Windows.
After install, tried several times to register my product key with no success, so decided to test Windows 10 as is, and see what the hoopla is about.
I learned immediately that 2 GB of RAM is insufficient for Windows 10. The actions were noticeably sluggish compared to Windows 7. (an SSD boot drive would have been better). I tested some of the built offerings and the installed some applications.
Being a Mozilla products fan, I was curious to see how the new MS Edge browser works. It looks exactly as IE 11, perhaps it is faster than the old IE11, but didn't linger much to test it thoroughly since I never liked IE of any version.
So, installed Firefox, Thunderbird, TextPad text editor, and made some changes to suit my old work environment.
The W10 search feature searches the computer and the web which means that it activates Firefox, being the default browser but uses Bing to search the web. (DDG is my default search engine).
Be prepared for another bout of the usual Microsoft changes, rearrangements, dropped features, and a lot of time wasted to finding the solutions to features used in Windows 7.
After of about 2 hours of use, realized that I wasn't ready to re-learn everything. So, I rebooted the computer with the 32 bit Windows 7 repair disk, which found the mirror backup tucked away instantly, and after about 25 minutes I was back to using Windows 7.