Consistent failure at installing Windows 7 with BootCamp

Question

A couple of weeks ago the 1TB hard drive of my mid-2010 21.5 inch iMac died, and I had it replaced with a 2TB hard drive.
As an architect, it is important for me to have access to Windows 7 (at least) so that I can make use of the Autodesk Revit software, among other programs. It is very important that I install Windows 7 on my new hard drive ASAP!
My SuperDrive seems damaged; it has trouble reading disks, as well as burning them (i.e. it simply cannot burn disks) and to circumvent this I purchased an external disk drive (a "LaCie Slim DVD" USB connected disk drive) which I have plugged in to my iMac. While I can confirm that this drive works fine - it was capable for one of burning a disk at 8x - I am encountering a problem when I try to restart the computer and commence installing Windows 7.
Specifically, I get a black screen (in the microsoft DOS kind of style) with a line of text saying, roughly: 'No boot disk detected -- please insert a boot disk and press any key to continue'.
Obviously, my boot disk is inserted. I have tried using Startup Disk to force the computer to use the disk in my external disk drive, but it hasn't worked. I have even tried using the old, damaged SuperDrive in the iMac but it presents me with the same screen. Sometimes it seems as though the external drive isn't activated when I start the computer - but other times it does have a glowing green light and makes that disk drive noise - even when the black screen with 'No boot disk detected -- please insert a boot disk and press any key to continue' is showing.
So what is my ultimate question?
How can I install Windows 7 on my iMac with a busted SuperDrive, using my external Disk drive that my computer seems to be ignoring?
I know MacBook Air laptops are capable of installing Windows with a USB - is that right? - can a very clear tutorial be provided to me as to how I can go about doing this?
I simply have to have this installed on my computer so I can access Revit ASAP, please help!

Answer 1

There could be another workaround, but I hesitate to mention it:
Install Parallels Desktop 9 for Mac and use it to create a Windows 8.1 virtual machine.
DISCLAIMERS:
1. I have not tried Parallels Desktop 9 under Mavericks, nor Windows 8.1 under Boot Camp under Mavericks, so this is not a personal endorsement, nor can I provide specific help because I'm still using Parallels 7, and Windows 7, not Parallels 9 and Windows 8.1
2. Parallels probably does not provide adequate performance for your Windows application software, compared with a Boot Camp installation.
3. There could well be compatibility issues with your Windows software and hardware. The mainstream stuff like Microsoft Office is fine. The more esoteric the software and more specialized the hardware (digitizers, plotters, 3-D printers), absolutely no guarantees.
So, Parallels 9 allows you to create virtual Windows machines that DO NOT REQUIRE BootCamp partitions, and you can install a legitimate copy of Windows from either a DVD or USB.
If you still want to give it a shot, download a free full version of Parallels Desktop 9 for Mac for a 14-day free trial here:
http://www.parallels.com/products/desktop/#tab4
Once the free trial has expired, it's $79.99 to purchase a license for one machine. You do not have to re-install and re-download if you purchase a license. you simply install the license code into the trial copy. If you already own a recent version of Parallels, there might be a less expensive upgrade available for $49.99.
I have successfully installed my legitimate OEM copy of Windows 7 64-bit copied to a USB stick, while running OS X 10.8.5 with Parallels 7, and my legitimate OEM copy of Windows XP from CD. It's not strictly plug and play. You do have to configure the Parallels Desktop settings to know where to look for the Windows installation files.
There is also VMware, and other virtual-machine software out there, but I have no experience with them.