I purchased Start10 via steam about 4 months ago, and it had worked fine until today. Now, it refuses to recognize that it is a paid for product, and only gives me the option of buying it again, uninstalling it, or running a trial version, while holding my windows button hostage.

Steam will not help with technical issues for this product, and won't give me a serial key for it. How do I go about getting that? I still have the receipt email for it, and it is still in my steam library.

What should I do at this point?