Looking to replace an hp a1730n amd mother board

[Noizemonger]

I would like to replace the hp a1730n desk top AMD motherboard (Am2) Athlon 64xll 4600 CPU with the asrock a785g-Le for 60$ from new egg. I'm running windows 7 32
I'm doing this so later I can install am3 quad core. It supports am2, am2+ and am3.
Can I just replace it an start it up or do I have to buy a new os?
Low budget building, some advice would be nice...will buy a new rig in 2 years, well I would like to wait....

My build:
Amd Athlon 64x2 4600
850w black widow thermaltake psu
4g ram 533mhz
Gtx 650 ti sc 2g video ram
24" dell 5ms hd monitor
Rocket fish CPU cooler
Note: I play skyrim on high settings

 

[Calvin7]

The new motherboard uses a completely different chipset so you won't be able to just connect your old hard drive and start it up.

 

[Noizemonger]

Hmmm. I thought maybe since the motherboard was compatable with am2 CPU there would not be an issue. (Was even going to get the 1066mhz ram
Upgrade too)
I didn't think about the hard drive...the chipset thing ill have to study more on...well it's fun to learn about this stuff...any advice on a motherboard that might work for what I'm doing to hold me over...if I'm SOL then that's that...lol btw thank you for the advice!