live usb - How should I go about demonstrating Ubuntu on someone else's system?

My relative saw me using Ubuntu and asked me about it. I suggested him to try it. He asked me to show it in his pc, to try it.

I recommended him to use the Live USB stick and try with it or install it as an app in windows. I have an Windows 7 pc as his is an Windows XP so I don't want to take any risks, if something goes wrong I'll be blamed!

These are the system specifications:

1. Operating System: Microsoft Windows XP Professional 32-bit SP2


2. CPU: Intel Pentium E5700 @ 3.00GHz


3. RAM: 2.00 GB Dual-Channel DDR2 @ 399MHz


4. Motherboard: Intel Corporation DG41RQ (J2E1)


5. Graphics: E2041 (1280x720@60Hz), Intel G41 Express Chipset


6. Hard Drives: 233GB Seagate ST250DM000-1BD141 (SATA)

So how do I go about doing it , He has few PCs to run at office and at home. So which version of Ubuntu would suite him and which would be the best way to let him try it (live USB or as an application or otherwise)?

Please help me, and explain the process in detail.

I am dual booting Ubuntu 12.04 LTS (32 bit) and Windows XP (32 bit) and both the OS's run perfectly fine on my system.I would recommend you also to install Ubuntu 12.04LTS (32 bit) using a Bootable USB on Separate partion. I had followed this link to install Ubuntu 12.04 on my system.