I started the game and for some reason my movement in-game is extremely choppy, with heavy lagging between my pushing a key and my actual movement.

We are very sorry of this issue.
It is indeed a sound problem (bad sound drivers for vista are making the whole sluttering) You need the 1.3 patch and/or to update your sound drivers.

To find out what sound device you have, please run the DXDiag

What is a DXDiag ?
DXDiag is a diagnostic tool that provides all technical info of your computer (as the name of your graphic card, space available on your hard drive or the version of the OS) No confidential info is given.

How to create a DXDiag ?
1. Click on Start then Run.
2. In the field Open, type the command DXDIAG then click OK.
3. Wait till the program has finished to collect all data
4. in the DXDiag window, click on the button Save All Information
5. Choose the place where you wish to save it and click on Save
6. Once the save done, you can close the DXDiag window and open the file DXDiag.txt

On your dxdiag you can find the name of your sound device, look for "sound devices" and "description", once you have the name, you can go to manufacturer web site (for example: http://www.realtek.com.tw http://www.via.com.tw) and search for the new drivers there.

To download 1.3 patch for The Awakened please use one of this links:

http://www.gamershell.com/download_18590.shtml
http://www.shacknews.com/file/10042/sherlock-holmes-the-awakened-13-patch