From what I understand, you had not streamed your Slingbox which was working previously on your laptop for some time. I do apologize about that, as trying to resolve issues on a computer are a little more difficult and time consuming. I would try the easiest step first.
Try uninstalling any plug-ins you may have installed from your computer. Make sure to uninstall everything that has Sling in it. Once that's done, go back to newwatch.slingbox.com and connect to your Slingbox. It may take a few minutes before you're prompted to re-install the plug-in. If you have any questions or concerns, please let me know. Hope this helps!
Sling Media Moderation Team