I have one computer, can I run two separate OS's?

This is Leonidas, my current PC.

Case: NZXT Phantom 410 - White

CPU: Intel Core i7 OC'd at 4.1ghz 

GPU's: Two GTX 670's in SLi

RAM: 8GB's DDR3 1333mhz ADATA Gaming series

Mobo: Z68 Asrock Extreme 4 Gen 3

CPU Cooler: Corsair Air Series A50 CPU Cooler

PSU: OCZ 850w Gold Certified

SSD: Crucial M4 256gb

HDD: 2TB thingiemajig

Steelseries 7H Headset

Steelseries Sensei Raw Mouse

Steelseries Qck Microfibre Mousepad

Logitech 5.1 Surround Sound System

A surprisingly good mechanical keyboard that I use, because it's loud..

 

I also have an external 500gb HDD and I've been thinking, if I were to rip that open, put it in my PC then I could put Ubuntu on it. I'm thinking of doing this as a sort of learning curve, the PC I currently use was built by a relative because of it's price and my inexperience at the time.

So my question is: Can I put another HDD into my computer, put Ubuntu on it whilst booted on Win 7 and then boot up again in Ubuntu?

If so, how? I know how to get the HDD into the computer and hooked up properly but past that I don't know what to do nor do I want to damage my Win 7 "Boot".

YES! you can download the windows ubuntu installer and then select the new HDD after you installed it to be the boot drive for ubuntu then when you start your system you should be able to choose between ubuntu and windows!

http://www.ubuntu.com/download/desktop/windows-installer

i was going to suggest as said above ^^^^

if your gonna install with windows and a none windows o.s. you best install the none windows 1 first as i find that windows doesnt play well with others if its put on first. you must  partition the drive with windows initally so the mft is setup correctly. win xp,vista and 7 all have slightly different mft setups so make sure you make new partiutions befor you start installing anything. 1s done reboot and start your alternate o.s install then windows.

 

 

I've got a HDD that I'll be using only for Ubuntu, this shouldn't conflict with my Win 7 boot on my SSD should it? Presumably the same would go for my 2TB storage drive.

it shouldnt as long as windows knows its there. i have had issues putting linux on after windows but none if i put windows on after.

www.wikihow.com/Dual-Boot-Two-Versions-of-Windows

i would divide your hard drive into 3partitions.

partition 1 - 40 to 45% of the hardrive

partition 2 - 40 to 45% of the hardrive

partition 3 - 10-20% dido

you will wamt to have the third partion to dump data that can be sheard between the two Os's

You dont have to do anything like that I run windows 7 on a ssd and I have a 1tb Hdd for storage but I also have a 320gb HDD for just ubuntu as long as you dont store windows files on that drive it will play nice

There seems to be a tad bit of confusion with which drive's will have what on them and how I'm storing shizzle, but thanks for the partitioning suggestions as that might be something I decide to do.

I currently have a Crucial M4 256gb SSD for Win 7, and a 2TB HDD for storage drive for games, programs and what not else. I'll be putting in a third drive, a 500gb HDD for Ubuntu and restructuring my storage drive so that upon accessing it the user would be presented with two files:

Win 7 Folder: All my games, programs, video's and what not else that I use / need when using my windoes boot.

Ubuntu Folder: The exact same mirrored structure, only this one contains my Ubuntu things used when in my Ubuntu boot.

I may yet partition my 500gb HDD 20/80 with one partition being solely for Ubuntu's OS and the second being for storage of my Ubuntu things.

Thanks again for all the suggestions on what to do.