ESXi, USB and boot issues

For the past 3hrs I was trying to install ESXi 5 on a desktop PC using a Flash Drive. All the times install went fine but it won’t boot. I thought maybe there was an issue in Flash drive but it didn’t work. Tried multiple combinations, read numerous articles but write-boot-install-failed!

Finally found the issue! ESXi 5 by default format the HDD in GPT and my BIOS won’t read it. Its an old motherboard. During initial boot you have to press [Shift+O] and after ‘runweasel’ insert a space then type formatwithmbr. 

Now uploading ISO files to data store.