Hi Muhamed,
One other thing, it<s to be sure to get all the drivers you need, pointer, usb, wifi card etc etc, before installing windows 7. It's a pain in the "bucket" to have a latop on windows and missing driver.
Check the manufacturer's site to see if Windows 7 drivers are available for your computer. As has already been mentioned it will be a big hassle if the drivers are not available.