I downloaded an ISO of the install DVD for 7pro, but I don't have a DVD burner. (I am upgrading from 32bit to 64 bit and therefore can not simply upgrade.) A backup install disk is also coming in the mail, but it could take three weeks and I don't want
to wait that long. If I put the iso on an external hard drive, can I use that to install?
You would extract the files from the ISO and then replace the drive letter of the DVD drive with the path to the extracted files. In terms of installing from SD card in a desktop PC it should work since the SD card readers in desktops are usually USB and
the reader is a USB mass storage device i.e to your BIOS it is the same thing but from. In a laptop I am not sure, you can try....
There is no reason it needs to be 8GB... as long as the contents of your ISO will fit on the drive it is ok. My Windows 7 disc from Dell was ~2.5GB.
But anyways Microsoft has a tool to do exactly what you want. I can't find a microsoft.com download link but here is cnet link for it:
" The Windows 7 USB/DVD Download tool allows you to create a copy of your Windows 7 ISO file on a USB flash drive or a DVD. To create a bootable DVD or USB flash drive, download the ISO file and then run the Windows 7 USB/DVD Download tool. Once this is done,
you can install Windows 7 directly from the USB flash drive or DVD.