Very minimum spec
1GHz processor -- 256 Mb RAM -- 20Gb Hard drive -- Floppy Drive -- CDROM -- 15" screen -- Keyboard -- Scroll mouse -- Graphics and sound on the motherboard. Plus printer to taste and Windows XP Home.
You can get all free software other than the OS, if you've a mind to.
This will do what you want with the greatest of ease.
You will find some upgrades on this very basic spec cost you very little, and may be with having - but it's up to you.
Best upgrades are
40 or 60 Gb Hard drive -- 512 Mb RAM -- Larger screen, 17" -- Faster processor.
It all boils down to what you want to spend above the very minimum.