[xdude]

I did create a similar thread while ago about small Linux versions which you could run by a USB. This is possible but if I remember correctly you need a bigger pen drive than 8GB. These days everyone has drives bigger than 8GB. This has its own drawbacks as well as it's not that easy to get it done. But in your situation, I guess you need it. Also, you said you have Ubuntu in your drive. This is the drive is a bootable one? If not then you will need to create a bootable USB first think. I really don't remember all the facts though.

You can do the same with Chrome OS but you need another PC to set up your Pendrive for all of these things. Maybe from a friend's PC?