Hello terajiv;
There is no BIOS version 1.6 available. The latest version is 1.18 dated 04/11/2011.
All ACER BIOS downloads have both the Windows and DOS versions in the zipped package.
Create a bootable CD or USB flash drive. Copy the Dos installer ZR7_118.exe file to the CD/flash drive.
Bootup the CD or flash drive and execute the ZR7_118.exe file at the command prompt.