you could try to install win7 with the upgrade version with this here guide,
(this was mentioned by another member here on another thread recently, but i forget who or which thread. whoever it was, you know who you are, so credit to you for the find.)
^ that guide looks like it has a good chance of working, but if you just want to stay safe, but the version that i linked you to earlier.
and make sure its 64-bit.
that deal doesnt look too bad. the psu that comes with it isnt the greatest one, but if youre still gonna go with the 4670 as a dedicated gfx card, yes it should work.