I am using WLMM to create video (around 2 minutes long) and it does not playback the video smoothly or just stops during a playback which is making it very difficult to edit. 

I have looked at the driver using the dxdiag command that was suggested in other posts similar to this one.   

Main driver: igdum64.dll,I gd,10umd64.dll,igd10um (can't read rest of driver)

Version: 8.15.10.2712

Date: 27/03/2012

Whql logo'd: yes

DDI version: 11

Driver model: wddm1.1

I am using WLMM version 2011 (build 15.4.3508.1109)

Majority of the video is from sony handycam and are .mpg files.  Also have some footage from ipad which is .mov file, there is no difference in functionality of either type of file, both get 'stuck'. 

Using a Lenovo Z580 laptop which has windows 7.

I will try the window fix-it suggested in the other similar threads however I am worried that your link took me to 'PC utility kit' by red dog media and that this is a virus? 

I would be grateful for suggestions in how to solve the problem of the choppy playback as I really want to finish creating the movie.

Thanks

Claire