I have made a bootable USB flash drive to do a clean install of W.10, I understand this will enable me access to the 'Custom: Install Windows only' option, which will also enable me to do a dual boot & install W.10 on a partitioned drive which I have already made & called 'G:' drive. I have tried once to boot from this drive without success. I have an Acer Aspire V5-571P built in Sept. 2012. I went into 'Settings>Change PC settings>Update & Recovery>Recovery' & noticed the 'Advanced start-up'. Should I be using this, or not? Thanks for any assistance. I am quite happy with W.8.1 but thought that it would be advantageous to install the free W.10 for the time when they phase out W.8.1.