External hard drive on laptop running OS?

Hello guys, for the next months I will be using a friend's old laptop with the following:
Notebook: Acer TravelMate 3273WXMi
Operating system: Windows XP Professional, Version 2002, Service Pack 3
CPU: Intel Core 2 T5500 at 1.66 GHz
RAM: 1014 MB

Now, I know that XP is bad and I should change them.
But, I want to leave them as be. (Its a borrowed laptop)

I am planning on using an external HardDrive (500 GB) with Linux in it, Debian or a lightweight Ubuntu variant. (Probably without desktop, the less ram used the better)
(http://www.debian.org/releases/jessie/amd64/ch03s04.html.en)
Also, I want it to run Matlab 2007, at least. (http://www.mathworks.com/support/sysreq/release2007b/linux.html)
I think that I can make it. What's your opinion?

My questions are:
Can I use Linux from an External Hard Drive?
If I can, can I use them as the main operating system? What I mean is, like a completely separate system?
This laptop could have a virus (I hope not, but I just got it and you never know), so I am just asking if I can completely separate them.

I don't know If that's right place to post this topic, but whatever the case is, thanks in advance!

If the laptop will boot from a thumbdrive, you could boot Ubuntu from it and run your programs from the external drive.  Perhaps you can configure things to boot from the external drive and not need the thumb drive, I just don't know because I've never done it.  Perhaps others will have better advice.

 

If you do this, you won't be using windows at all so any windows infection wouldn't be an issue…just don't run anything on the harddrive to be safe.  If you don't boot windows and don't use any of the windows programs… you have separated them.

yes you can do what your wanting without any problems with linux.

 

 

should add any lightweight desktop like xfce or lxde will run fine on a pc/laptop with those specs and ram, no idea about mathlab 2007, it looks very old and not upto date so no idea if you'll have dependency problems with the much newer kernels and libs of todays distro's.

I didn't know that about Windows viruses on Linux. That's nice to know.

I will work on the Matlab, I don't think I will have an issue.


I am a bit tired now. I got bitten by a stray dog today & went to the hospital.

Anyway, thanks both of you!
I will see what I'll do & might post any upcoming questions.

Have a nice day