Hi, I want to install any Snow Leopard in my laptop but I don't know how do it I have Windows 7 and Ubuntu 11.04 I tried diferents versions but it don't work anyone can help me plis┐?

Caracteristics of my laptop:
*Acer Aspire 5741G
*Intel Core i3-350M processor(2.26 GHz, 3MB cache)
*NVIDIA GeForce GT 320M Up to 2747MB Turbo cache
*15.6" HD LED LCD
*4GB DDR3 Memory
*500GB HDD
*DVD-Super Multi DL drive
*Acer Nplify 802.11b/g/n
*6-cell Li-ion battery

Sry for my bad english I'm spanish =S