Hmmmm that went a bit over my head. I've been using Rufus to try and load the iso's onto a USB stick, as it seems to be the only USB imaging tool that allows you to select a UEFI partition scheme (ie it has either MBR for UEFI or GPT for UEFI). All the iso's I got off the link you posted won't burn as UEFI because Rufus inspects them and knows they don't have UEFI support. The Win 7 64bit ISO does, but I can't get it to boot properly (and yes the Acer is 64 bit).
So I've downloaded the Centos ISO (minimal) and Rufus can use it to create UEFI (GPT) boot stick, which is now successfully booting under UEFI mode. I can break out to a Grub command line but I have no idea what to do next. Sorry for the ELI5 request, but could you help me with how would I re-partition the SSD to legacy MBR from here? Thanks in advance.