At part two I'm havin trouble. My snow leopard disk is in but, it wants to reinstall ML instead. I start it up and hold down the option key then it's like do you want to run the computer using the snow leopard disk 10.6 or whatever. I click yes and after

What exact model iMac do you have?

 > About this Mac

Attempting to install a version of OS X earlier than what was originally installed is not recommended and will probably fail:

Don't install a version of Mac OS X earlier than what came with your Mac

Are you using your original System Install DVD - the one that came with your iMac?

iMacManny wrote:

I have a mid 2010 iMac.

Ok, this model of iMac came with either 10.6.3 or 10.6.4 originally,

so the 10.6.3 white retail disks (image below) won't work in this machine if that's what your using.

The reason for this your iMac was released and requires hardware drivers not found on the disk above.

So what your going to have to do is call Apple via phone and order your Mid 2010 10.6 machine specific disks (don't mention Lion or Mountain Lion)

When they arrive then review the instructions on these links to restore your iMac to Snow Leopard.

How to revert your Mac to Snow Leopard

and others

How to erase and install Snow Leopard 10.6

Most commonly used backup methods

Drives, partitions, formatting w/Mac's + PC's

https://discussions.apple.com/community/notebooks/macbook_pro?view=documents