Welcome to LQ.
As Keruskerfuest has mentioned, more detail would be useful.
I am assuming that W7 was already installed on this Acer Aspire E15 when you bought it?
Windows should always be installed first, before adding Linux.
I know from experience that in order to make modifications to the Setup/BIOS on certain Acer machines, it is necessary to set a temporary
Don't forget to remove it afterwards.
This thread may help you: