have a msi z87 gd65 mb, I thought I enabled windows 8 features but on start up/restart I it is a t the efi shell with a device mapping table and "press ESC in 1 seconds to skip startup.nsh, any other key to continue. but ether way or leaving it only results in Shell> how can I get back to BIOS or run windows 8 which is installed and was working till I changed the setting in BIOS