I recently got a new computer and installed skyrim on it. On my old computer, skyrim played wonderfully on full graphics even with some mods. Now, I can't even play on medium graphics without mods or skyrim will have lag between my mouse movements and my cursor movements. It doesn't show up on low graphics, but i'm really upset that I can't play it with better quality. My current specs are:

Windows 7
AMD FX-6100 Six-Core Processor
10.0 GB of RAM
64-bit Operation System
1.5 TB of space on a HDD

Does anyone know why this happened?

You need to update the drivers? (Particularly the graphics)

Make sure you are using the 64bit version of everything as well.

Not enough information - http://www.gamesas.com/topic/1122570-how-to-dxdiag/ in spoiler tags.