How can i make/install windows 7 using my external hard drive ?

No, no. I did change boot device order even before I came here asking for help. I merely manually booted from the external HDD this time.

I cannot remove the entire HDD content, since it has multiple partitions that I cannot definitely remove.

Kaktussoft said:

manually Install Windows 7 From USB
or maybe easier for you Microsoft Store Online

Thank you. I will give it a try once I buy a USB Flash Drive.

gregrocker said:

If this isn't to your liking then you'll need to buy or borrow a 4gb flash stick ($5 with free shipping on buy.com) to write the ISO to it using Universal USB Installer with Win7 in dropdown menu. You'll need it for repairs anyway.

Three days ago I gave the easiest method to do this and warned repeatedly that trying to install from external HD is a can of worms.

Since that time there have been pages of Command Line code posted which chases away all but the most experienced users (including the OP). I fear this mess is going to represent this forum's help quality in Google searches.

If the Universal USB Installer won't write the ISO to your external, get a stick.

gregrocker said:

gregrocker said:

If this isn't to your liking then you'll need to buy or borrow a 4gb flash stick ($5 with free shipping on buy.com) to write the ISO to it using Universal USB Installer with Win7 in dropdown menu. You'll need it for repairs anyway.

Three days ago I gave the easiest method to do this and warned repeatedly that trying to install from external HD is a can of worms.

Since that time there have been pages of Command Line code posted which chases away all but the most experienced users. I fear this mess is going to be representing this forum's help quality in Google searches.

If you are ready to listen now: buy as $5 4gb flash stick and write the ISO to it in five minutes using Universal USB Installer

I couldn't agree more.

I used the tutorial to help me create a universal installer on a 6GB flash drive and used it to install Windows 7 SP1 in roughly 30 minutes.