Switching from Win8 to Win7 will replace Win8 on your HDD so follow the instructions to backup your current system (1xDVD, 1x16GB USB stick).
All the information is available on the forum in a number of excellent posts - perform a search and read all you can find before you do anything! There are a few 'Gotcha's' you will need to watch for but, as I say, all the info you need is here.
It’s time to recognize brummyfan2 for his dedication and collaboration. Please join us in welcoming brummyfan2 to our ACE Team! brummyfan2 has been a valued member of the Acer Community since 2013, eagerly helping users troubleshoot their products.