How Do I Boot From An External (USB) Drive?

How do I boot from an external (USB) hard drive? I've followed ALL the steps I've been shown in videos and on help pages and nothing seems to work. I'm new to Windows from OSX, and I'm starting to regret my switch.

I've gone into the damn BIOS thing like TEN TIMES and I've changed the "boot order" and I've selected "save and exit".

However... every time I start up my computer, it just boots from the internal hard drive?

What am I missing?

Please help! I really don't want to have to spend another 3k just to get a computer that WORKS, but I'm reaching the end of my rope here. This REALLY shouldn't be that hard!

Thanks

Generally there is a key you can hit to bring up a boot menu but without knowing your system we can't tell you what specifically it is. You can try looking through your computer's documentation for the key or perhaps the initial screen will say. Also note that the drive must have bootable information that the computer understands. From what I know about Mac though if you are trying to use a drive from a mac system a pc won't likely be able to us it.

I'm trying to boot into Windows 8 that I have on an external drive.

All I know about 8 is that I don't like it. I have only run it on a virtual machine. All I can offer is advice on finding the boot selection key. You might want to try our eightforum. Perhaps someone there will know Windows 8 Forums

I bought a Windows 8 laptop. It was 64 bit, but I run some essential plug ins that are only 32 bit. Because of this, upon receiving the computer, I immediately took the hard drive out and put it in an enclosure. I then installed a new hard drive, purchased a new copy of Windows 7 32 bit and installed it. Now I'm running into the problem that some of the new main software that I use is ONLY upgrading as 64 bit. I then found out about the existence of things like jbridge, that allegedly allow one to use their 32 bit plugins within a 64 bit machine and hosts. I wanted to boot into 8, which is in the external usb enclosure and test out jbridge, before I put the original hard drive back in the machine.