There's no point throwing multiple instructions at once, like booting a CD-ROM and unplugging the hard disk all at the same time won't do much good. Let's just make sure the foremost tasks are done before committing to reinstalling the OS or messing about with hard-drives. Of course, some or all of this may have been done already but I rather be sure of that.
Now then AJ, going by your description of the problem you are getting stuck between post and the loading of the Operating System.
First things first, unplug any USB hardware such as network adapters, cameras, lava lamps, removable media (aside of any hard disks that are essential to the loading of the Operating System), and anything else except the mouse and keyboard.
Now attempt to access Safe Mode by tapping the F8 key immediately after the post screen has loaded. You would normally be shown a menu with several boot options for Windows. If you see this menu, select the first option, Safe Mode. If the menu does not appear then the problem may well be hardware-related. Otherwise, if after selecting the Safe Mode option Windows still does not load then it is most likely an OS issue. In any case, this is the first step to take when diagnosing the problem.
Failing Safe Mode, gather any bootable disks that you may have, such as Windows set-up disks, commercial anti-virus products or others such as Bart PE. If they do not load after the post screen, check your BIOS settings to determine the boot priority. Where exactly the settings are within the BIOS will depend upon the motherboard (see here for some examples). In general, the CD or, preferably, DVD drive should be the first on the list (I would say floppy, but they are essentially useless now), followed by your master hard-drive. If the settings are correct and the disk is usable but it does not boot (and you have rebooted the system a few times to be sure), the problem may again be hardware-related.
Let us know here if you have succeeded with Safe Mode otherwise if you have managed to boot any CD or DVD and, if so, exactly what disks they were.