I have a Toshiba L50-A0424 laptop. I created a Win10 bootable USB and tried using it on the laptop. This didn't work with UEFI so I read somewhere that if I changed to CSM I could boot from the USB. Bad mistake! The laptop is now stuck on the 'Check cable connection. PXE-MOF error. To make matters worse, no matter what I do I can't access the BIOS so that I can revert to UEFI. I've tried pressing F2, F12, Esc, Esc/F2 and the entire range of Function keys, no help. Have tried resetting the BIOS by removing the CMOS battery, doesn't work. Am at the end of my tether, any ideas on what to do ?