I second forcesho's vote for Norton Ghost.
Let's you dig your self out any software hole you can create.
Your fiber NICs probably come with a setup program. Remove Old adapter in network properties, shutdown, remove old NIC install new NIC, reboot, run vendor setup program. If no setup software just add adapter from network properties. Forcesho's method is more thorough, but I'm a bum.
Now, you are replacing workstation and Server nics? Just in case this didn't come up earlier. You are going to need new cabling and a new switch, not to mention that you need special tools if you want to use bulk cable. But I'm sure you know that, I hope you know that.