I have never worried about the WEI. It's very misleading since the final score is based on your graphics card anyway. I mean, I used to work on a 2.4Ghz Core2Duo with 4GB of RAM running Vista Pro. The overall WEI was like a 2.5 because of the integrated Intel card. Does this mean the machine was that slow? Nope. I could run all the programs I needed to run (a browser, Excel, Adobe Reader, and Word) with no lag. If the machine works overall, don't worry about the Windows rating.
Thank's for information so I won't worry about it as I can do every thing I need to do.