Will you consider purchase one more harddisk for your noteook, then you can keep all Windows 7 OS, and original software from Acer. For someday while you are interest in Windows 7, you can an Genuine Windows 7.
You can change the harddisk,it won't expire anything!When something wrong need to return to factory then install the original harddisk back.
《Caris》is best idea。
Or go format the harddisk to made two partition to install each OS each partition。
I'll hope can help you?