I had to erase 32bit Windows 7 Professional on my custom pc, i have 16gb not knowing that windows 7 32bit only supports around 4GB. I found ISO's of the windows 7 editions that are 64bit, but I cannot understand why the ISO when i boot on my usb to my computer says that, "error" unable to boot from USB windows 7. I also use 1 SSD and 1 TB HDD, Please help !