I need someone to school me on the different Microsoft servers and the pros and cons of each.

We are currently using Windows Server Standard 2008 with SP2

There are two updates that keep failing to install and I've read that I need to put the DVD in and run setup to fix some corrupt files.

updates:
Security update for windows server 2008 x64 edition KB967723
Update for Windows Server 2008 x64 edition KB2443685

error code: 80070490

The server software was installed by an IT company a couple years back. I'm worried they may have used a universal copy of windows. We don't have a DVD for it. To get one I need the product ID number. Still need to confirm if there's a sticker on the tower or not as I'm at a different location from the server.

Anyhow, just in case we do replace the server software with a newer version I want to know what my decision needs to be based on.

Server specs:
Quad-Core AMD Opteron(tm) Processor 1354 2.20 GHz
8.00 GB ram
64 bit OS