Yes you can have the Mac OS on one drive and Windows on another drive. Or you can partition a single hard drive and have both on the same drive.
I'm not quite sure what you mean, so I'll give you both answers: "How do you use a hard drive for Mac and Windows on the same machine?" On a mac, insert a Windows install CD or DVD, and the computer will ask you if you want to set up windows to run alongside mac. In the process you will partition the hard drive, so you will kind of have a windows hard drive, and a mac hard drive, but on the same disk. "How do you remove a Mac hard drive and put it in a Windows machine?" I am not a technical expert, so you might want to look up "How to remove and install a hard drive". All I know is it probably won't fit, so you might need to buy a hard drive enclosure and run the drive from a USB port. Hope one of these helps! If not, please revise your question
You can certainly move Windows to an external hard drive but Windows will not boot directly from an external drive. If you are running Windows in Parallels (See links below) you can have Parallels installed on the Mac's drive and then have your Windows virtual machine on the external drive.
Providing the Mac is a recent model with an Intel processor you could make a Mac into a Windows only machine or you could partition the hard drive and have both Mac OS X and Windows as options.
Yes if you get a Virtual Hard Drive of the Windows Software.
A Hard Disk Drive (HDD for short) stores your files. In most computers running Windows, your primary hard drive is represented by your C: drive.
If Mac: CD Reader, A-4 microchip, speakers, motherboard, hard drive Windows: Not Sure
Hard drives for windows and OSX vary in size and model, check or ask about your computer brand. You can also check in My Computer (for Windows) or Macintosh Disk (for Mac OSX).
Assuming you're talking about transferring files from a Mac to an external hard drive (since this is the Apple / Mac section), here is one possible scenario: If the external hard drive is NTFS formatted, then the Mac will only be able to read the contents of the drive, and will not be able to write to it. To remedy such a situation, back up all data from the external hard drive, launch Disk Utility on the Mac, select the hard drive, and format it as 'Windows / MS-DOS' (FAT 32) format (if you'd like to keep the external hard drive Windows compatible), or format it as 'Mac OS Extended' if you're only going to be using it on Macs.
You cannot just download and install Windows on your Mac. To install Windows on your mac you will have to partition your hard drive and then install Windows on that new partition. This will have no effect on your existing OSx. To do this you can use Boot Camp already installed on your Mac or Parallels which you must purchase.
You can not, unless you add Windows to a partition on your hard drive, so you can dual boot and play CE on Windows. Otherwise, it is impossible.
The Windows formatting is probably MS DOS FAT 32 or NTFS. A Mac will be able to read from such formatted discs but will probably have problems writing to them without the aid of software such as MacFuse (See links below) . If you have no need for the Windows formatting connect the drive to the Mac. Open Disk Utility which is in the Utilities folder within the Applications folder. Select the drive from the left hand pane and select Mac OS Extended (Journaled) from the Volume Format drop down menu.
yes, open your bootcamp assistant and select remove partition.