Nice english...
1st.) When installing OS there is no way you can damage your motherboard.
2nd.) Look Around the forum... In Open Source section u can find guides for every distro... See here
Guides for different distros
3rd.) Google the term "How to install ubuntu" click any of 1st 3 results.. You will get full step by step guide to install it... Ubuntu is easiest to install... Easier then windows. Even for someone who is a new to computers... (u must know english though to understand the instructions.
)
Here is a step by step guide...
news.softpedia.com/news/ How-to-Install-Ubuntu-7-04-Windows-User-P-O-V-52973.shtml
and
Welcome to the world of Linux...