Possible upgrades for an old system

Hi beautiful people,

I am not an expert on OS X, but I don not understand why I can not upgrade my system.

Bought my computer in 2006 (yes it is an oldie but still I love it)

Type: Macbook Pro 17"

System: 2.16 Ghz Intel Core Duo

2 Gb 667 Mhz DDR2 SDRAM

Can I realize an upgrade by changing the RAM or something els.

Because now I get messages to upgrade Safari or Google and all the upgrades do not run on my system.

Or if not could I also change this macbook pro into an Lynux system?

Looking forward to your replies, would mean a lot to me to have this machine still working as updated as possible,

Musical happy and healthy greetings,

Bastiaan Athonie Baaij

www.reverbnation.com/bastiaanbaaij

Finland