"No Access to ACER ASPIRE V5 471 Bios (Operating System Not found)"に関する回答NON of this helped. I did try all of it before getting here. I even reprogram the bios with my special machine and nothing. So far the only thing it helped was booting with a w8/8,1 Core x64 dvd installation. By default most w8 bios had cd/dvd booting first than the hdd. The root of the problem is that you had your bios reseted to default somehow. GL!! PD: use f9/f12 to boot the dvd and wait for it to boot up. a good tip to know if your w8 computer came originally with 8 or 8.1 is to boot up the core version of each one and the one that does not ask for a key is the one. Also if you computer is originally w8 you can go ahead and install w10 and it will activate after changing in the bios the w8 key for the w10 key with no problem. I do it everyday even a year after the free upgrade is gone.. DONT WORRY IT DOES NOT BOOT TO THE BIOS OR IT DOES NOT SHOW THE BOOT MENU, just do it and it will work.