How version OS

Sorry, bat I don understand. How version OS I must download - 32bit or 64bit?
I have – Core Duo T2300 (1.6 GHz), 1 GB memory, ATI Mobility Radeon X1600…
Thank you.

32bit, is better for you.

Your processor is 64bit so you can choose. Since you only have 1GB ram it doesn’t make much difference. The 64bit will let you use more than 3gb ram if you choose to get more in the future. If i was you i would get the 64bit.