Problems updating from 10.6.8

Hey there everyone,

Just looking for a bit of help updating the firmware on my MacBook.

It's currently running 10.6.8 and prompts me regularly to update. When I agree to update and confirm it all, it goes to a download screen (presumably to download the updates) but this disappears really fast, like within 2-5 seconds.

It then comes up to restart and when I choose to do this it disappears to a galaxy background and just stays stuck there and doesn't actually do anything.

I've had a search around and it seems you can manually install updates and stuff like that?

I'm not too savvy with Macs and OSX so any help or guidance to the steps I need to take would be great!