You could save some dollars my going to a mobo with a 6x series chipset ... they are less than the newer 7x boards and still have a SATA3 connection.
You can get good 120GB SSD drives for about $60 on sale now ... newegg and micro center are pushing them most of the time.
You would be happier getting a little better cpu ... the Pentium 6xx chips are about $50 on sale now ... newegg has a G630 for $38 in an email I just got.
I just bought all the parts for a PC through newegg one deal at a time and paid a lot less than their good prices ... it took three weeks to get everything. Partspicker website also shows least expensive sources too ... if you are in a hurry to get everything.
Only thing i see that you are overpaying on is the ram. 4g can be found for under $20
both the build and prebuilt will suit your needs. differences are the quality of the parts you get. Benefits of a build is you get to pick and choose the parts, allow for expansions/upgrades, and it's fun! Benefits of prebuilt are convenience (buying and assembling), and Can be found cheap.
For something in between you can also try barebone kits and combos. I see them a lot @tigersdirect.
As for windows, I can not answer you out right with 100% certainty but I do know that they do not like 1 licensed windows running on more than 1 machines.