As for installing an operating system the choices are either Windows 7 or one of the recent Linux distributions.
You may choose to install a Linux system just to verify that your hardware is working alright. One version that I found very easy to install was
Linux Mint. It is available in both 32-bit and 64-bit versions. But more conservative thing to do with the 32-bit version first, then later do the 64-bit and see what difference there is.
After that, you might wish to decide which version of Windows 71 to use. The 32-bit version will work fine, but cannot make full use of additional memory. The 64-bit version of Windows 7 is very good and works fine, but has
one annoying problem. Some manufacturers have been slow about releasing
true 64-bit drivers for the devices they have. In particular, video graphics cards and wireless network cards . If you want to save money on the purchase of Windows 7, you have to buy the OEM 32-bit version and just be satisfied with that. The home premium is all you really need.
That's about all I had to say about operating systems.