Had this happen to me recently after I changed the motherboard, graphics card and CPU in my PC.
I used EaseUS ToDo backup workstation to take a full image of my system hard drive and then restored it using the "dissimilar hardware" option. Worked really well, just had to set up a few motherboard base devices afterwards. Which was not a big deal as I had previously downloaded drivers and saved them to a USB hard drive.
Anyways, I decided I wanted to watch a video on Lovefilm and as usual, I just fired up the web site, logged in and then chose what I wanted to see. Imagine my surprise when up comes "System.Exception error 6013 has occurred" or words to that effect.
Research I did indicated that it was a Microsoft Silverlight problem. So I uninstalled it, downloaded the latest copy and then installed it. Not that it changed anything, the error continued.
This was not a big deal to me, so I just gave up at this point.
Fast forward a week or two and I found myself wanting to watch something on Lovefilm again. Same error, again. Did further research and found out exactly what Silverlight error 6013 is and I quote;
"The user's HW configuration has changed in a significant way and the DRM state is no longer valid."
Well, that pretty much sums up my situation. What I had not yet found was how to overcome the bloody error!
More reading ensues and eventually the answer becomes available.
There is a hidden file that I can only imagine is a DRM hardware snapshot of your PC`s state at the time the file is created. it is named mspr.hds
and it can be found here: C:\ProgramData\Microsoft\PlayReady
Assuming that C:\ is your system drive of course, otherwise substitute the appropriate drive letter.
Close all Internet browser windows, navigate to the above directory and delete mspr.hds
Open up the Lovefilm website and choose an "instant" title to watch, the file will be freshly created and your choice should now play without incident.