Upgrade to Windows 10, or no?

Try Windows 10 on your USB hard disk using the method in the video without worrying about the current Windows system installed on the internal hard disk.
Microsoft has finally announced “Windows 10 Will Be Released July 29th 2015 as a free upgrade for users of Windows 7 or later”. You are probably eager to upgrade to Windows 10, but may be worried about upgrading, and overwriting your current Windows version.
Using the function, “Install Windows 7/8/10 on USB disk”, in “Lazesoft Recovery Suite”, you can install Windows 10 on a USB hard disk without affecting your current computer set up. With our new program version, you do not need to worry about any possible effects on your current Windows installation or the data on your internal hard disk.
This video shows how to try Windows 10 safely using new version of “Lazesoft Recovery Suite”.
Windows versions are becoming more and more portable. A true, portable, Windows version must support execution from a USB hard disk, as well as use a product key that is not located on the motherboard of the computer.
The older Windows XP cannot run after the motherboard is upgraded. It crashes when an attempt is made to boot from a USB disk. Windows 7 can support being natively boot from a VHD disk, and its boot volume can be located on a USB hard disk. But, the system volume, itself, must be found on an internal hard disk.
After an upgrade to the motherboard, Windows 7 can still work properly, if the computer’s CPU type is not changed (for example, from Intel to AMD). After cloning a Windows 7 to dissimilar hardware, however, a new license key is usually required.
Windows 8 and 10 can run from a USB hard disk, including one holding both the system and boot volumes. In addition, Windows 8, Windows 8 .1 and 10 have a new feature, “Windows to Go”, which allows an installation of Windows 8 on a USB hard disk. However, the feature, Windows to Go, is only available with the Enterprise version of Windows and on Certified Drives. For more information, you can refer to:
https://www.microsoft.com/en-us/windows/enterprise/products-and-technologies/devices/windowstogo.aspx
In our attempt to make testing and upgrading to Windows 10 as easy as possible for you, the new version of “Lazesoft Recovery Suite” has a new feature, “Install Windows 7/8/10 on one USB hard disk”. The new Lazesoft option can do more things than ‘Windows to Go’. With our new feature, every version of Windows 8/10 can run successfully on USB hard disk. Certified Drives are not required. Any common USB hard disk is good enough. If you list Win 7 on the option, can a user install that version, say on an XP machine? This is not stated very clearly, and might need to be included in several places in this article.

The following is download link of the new beta version of Lazesoft Recovery Suite Home Edition, which allows you to use the new feature, Install Windows 8/8.1/10 on USB disk:
http://www.lazesoft.com/beta/lsrshsetup_beta.exe

Here are the steps to install a Windows 10 preview on your USB hard disk using “Lazesoft Recovery Suite”. (WARNING, THE DATA ON THE USB HARD DISK WILL BE ERASED. SO, YOU NEED TO BACK UP THE IMPORTANT DATA ON THE USB HARD DISK FIRST)
1. Download a Windows 10 preview ISO file from the page:
http://windows.microsoft.com/en-us/windows/preview-iso
2. Mount the downloaded ISO to a new partition on your main hard disk (For example, mount to drive R:\).
3. Download and install the new version of “Lazesoft Recovery Suite”.
4. BACK UP ANY IMPORTANT DATA ON THE USB HARD DISK FIRST.
5. Launch “Lazesoft Recovery Suite”.
6. Find the button, ‘Install Windows 8/8.1/10 on one USB hard disk’, in the left action panel of Disk Image & Clone module of “Lazesoft Recovery Suite”.
7. For the install of Windows 8/8.1/10 on a USB hard disk, choose the target disk as the USB hard disk.
8. Choose the Windows installation mounted drive, (such as R:\). Sorry, is this drive selected as a ‘source’, where the Win 10 preview was downloaded?
9. Click <Start> and confirm that the hard disk is chosen correctly and begin.
10. Wait for a few minutes to one hour to let “Lazesoft Recovery Suite” to do the installation.
11. After the task of Installing Windows 8/8.1/10 on one USB hard disk is completed, exit “Lazesoft Recovery Suite” and reboot the computer.
12. Set the BIOS to boot from the USB hard disk.
13. After rebooting, complete the wizard for setting up Windows 10 and enjoy Windows 10,  bootable from the USB hard disk.

The video about “install Windows 10 on USB disk” using Lazesoft Recovery Suite.