Thank you for the post on our Answers Forum. I can understand why you would want to know the warranty status on your 500 and I have the answer for you. The warranty on the unit lasts for 1 year from the original purchase date. So if you purchased the unit today May 3rd 2013. You will have warranty until May 3rd 2014. You can find out the purchase date on the receipt you bought it with.
Here is a link on the full details of the warranty:
You can also check the date the unit was activated we typically go by that date for warranty as well. You can check this out by going to our support site which should populate a page with all your Slingboxes and their original activation dates.
Here are a few links about that:
If you have further questions you can always call in and we can check the activation date for you. Just contact our technical support line at 1-877-GO-SLING (1-877-467-5464)
Hopefully this helps out!
The Sling Media Moderation Team