How can I boot between 3 different operating systems?

You need to understand how boot.ini works: it’s a text file that specifies the items on the boot menu, it’s usually located on c:\ (or the root of whatever drive is marked “active” for booting). You can learn the details of boot.ini here:

http://en.wikipedia.org/wiki/NTLDR

Also, unless your home PC is very similar at the hardware level to your office PC, just dumping an image of an OS hosted on different hardware, with different drivers, etc… is an extremely bad idea – you will likely suffer BSoDs, have problems with programs and even booting the OS. It could also damage your hardware.

Thanks HasntBeen. My home pc and office pc use the same motherboard. The only difference is in the office I have a small Windows workgroup network. The video card is different too.

I disagree with @the100thmonkey about the consequences of putting in an unrelated image. The chances of hardware failure are very small, and in fact it isn’t uncommon for an “alien” Windows image, installed on unrelated hardware, to boot just fine—it comes up in a kind of safe mode, starts doing a plug-and-play install of the drivers for the motherboard, etc. I’ve done it.

But, it’s not guaranteed: it could fail to boot, it could be that this partition never really stabilizes, and yes… in rare cases it might actually damage something. But I’d take the chance, hardware is cheap.