Windows 7 Installation stuck

Hi.

Right, straight to the point. I've recently been given a few parts of computer from my friends that has now been assembled into a working desktop.
I've got Windows 7 saved as a .iso file on a usb-hdd. I manage to get it working up to the point where i click "Install Now" on the Windows 7 installer programme, then after a couple mins of loading once clicked it comes up with this message.

"A required CD/DVD drive device is missing. if you have a driver floppy disk, CD, DVD, or USB flash drive, please insert it now.
Note: If the Windows installation media is in the CD/DVD drive, you can safely remove it for this step."

There are 3 options that come up with this pop up being "browse" "ok" and "cancel"

After clicking "ok" it comes up with another message saying

"No device drivers were found. Make sure that the installation media contains the correct drivers, and then click OK."

Can anyone tell me what's wrong or what i have to correct in order for it to actually download please?

Computer specs are as follows:-
AMD Athlon ii x2 (3GHz)
Gigabyte M61PME-S2P Motherboard
WDC WD1600JD-75HBB0 Hard Drive (came from a Dell Dimension 5000, been wiped of everything.)
Kingston hyper DDR2 RAM (unsure of make so i've just written what's on the RAM itself.)
ATI Radeon HD 5750 Graphic card.
Some random CD/DVD drive
Another random Power Output

Thanks for your help!

AndrewM124 said:

Can anyone tell me what's wrong or what i have to correct in order for it to actually download please?

Download??? I don't follow that.

If I had a Windows 7 ISO, I would burn it to a DVD, and then install from the DVD.

Or am I misunderstanding something?

Sorry, by download i just mean for it to carry on in the process of installing win7

Have you tried to install by burning the ISO to a DVD, rather than using a "usb-hdd" as you state in your first post?

How will you activate Windows?

I haven't no as i have no spare DVD's around to burn it on to

I'm not sure you can install direct from an ISO--others would know.

DVDs cost about 25 cents. Try one.

I'll go out tomorrow and look for one! i'll see what other have to say first just incase i don't have to

Yes i have, it doesn't show up for some reason.