Frankly I didn't think it was possible to boot a standard PC (esp a laptop) from a SD card. Unless I'm missing something. Might be possible if you got an external usb card reader that fooled the bios into thinking it was a removable HD, but that's not what the internal card reader can do. I'm not aware of any hardware that could make it work.
You probably have to follow one of the many guides on the net describing a way to shrink your windows partition to be able to free up disk space for linux partitions.
I would think that the windows bootloader that gives you the option to either boot to Win7 or Ubuntu, has SD or usb drivers that it can access should you select ubuntu.
Should this not work?
I installed ubuntu from within Windows. No, no hard drive partitions were created. Rather the win7 boot.ini was created that simply points to ubuntu in the SD path, in addition to the win7 in hard drive.
Oh and so BIOS should not have anything to do with this. BIOS simply loads the windows boot loader. This bootloader then presents an option to either boot to Win7 or Ubuntu (it gets its information from the boot.ini file), and simply should boot to the path selected.
Hmm... understand... however the BIOS options do allow you to boot from an external device, it does not specify USB or SD though. So I made an assumption that it would allow booting from either of these interfaces, if the boot loader were to use BIOS calls to load OS from them.
I still would like to see if there is a way I could get my laptop to boot through an SD installation. Note: it installs fine. Do I have to format the SD in FAT32 maybe? I will give that a shot next.
With USB, there are various methods that the hardware can be setup to be recognised by the system, and the bios will only boot certain kinds. Its like 10 years ago, to boot from a CDrom (common by todays standards) you needed the disk formatted properly, the drive to support it, and the bios setup to boot from optical media. If you didn't have all three stars aligned, it didn't work. SD card readers aren't designed or setup to allow booting, unless specifically made to do so (I'm not aware of any). Yes, you can install onto an SD card, but that doesn't imply that you will be able to use it.
USB flash drives are a viable way to do this however, you can google and read up on that.