You can flash the BIOS also inside windows.
If you downloaded the BIOS_Gateway_R01.A2_A_A.zip file from the gateway page
extract the file to a folder like c:\BIOS\
Close all the programs running including the Antivirus software and any other security programs you have.
On the extracted files locate WINFlash.bat, right click the file and choose Execute as Administrator.
After flashing the BIOS shutdown completely the computer and then turn it on again after one or two minutes.