Well I have this old laptop, I bought it in 2009. It is an Acer 5720
INTEL CORE 2 DUO T7300 2.00 GHZ 2GB RAM Hard Drive: 150GB Hard Disk Drive MOBILE INTEL 965 Express Chipset Family
I tested Ubuntu 15.10 by the Live CD; It ran good, but I want to know if other "flavour" could run better than Ubuntu, or maybe an older version . Thanks
The latest version of normal Ubuntu can work perfectly on computers from 2002, so your laptop isn't old by comparison.
15.10 should be fine for you, but no one can predict what your experience is going to be, and that isn't the purpose of this site, anyway (sharing experiences).
You said yourself 15.10 worked fine, so I see no reason it shouldn't worm when installed. Of course, if you want the most performance possible, there are a few options.
Lubuntu is a version of Ubuntu known for being very lightweight, working well on very old computers, even 1999 iMac PowerPCs. Xubuntu is another option for a lightweight experience.
The best thing to do it just try out the default. If it doesn't work, install something else. You can go back versions (12.04 and 14.04 are still supported), but your laptop can certainly handle 15.10. It might even work with KDE, which is rather featured and thus resource-intensive.
Look up the official Ubuntu flavors (MATE is nice, GNOME is simple), find the one you like, and install that.
Good luck.
