Can you use a server as a normal PC?

Yes, you can. Just install whatever operating system you're wanting on the server and use it like normal. I know of a few people that have done this and I want to try it but I don't have a couple thousand dollars to blow on a server.

If you are fortunate enough to come by a SERVER UNIT, then all you have to do is wipe the hard drive(s), Format it/them and install your operating system onto the primary hard drive. Check the BIOS to determine this, make sure you have enough least 10 Gigabytes, which a SERVER should easily have...and set the primary drive to boot up first...easy.