What’s the difference between an iPad and an iPAD? In China, the answer could be $2 billion and a major headache for Apple Inc.

The technology giant says that it purchased the iPad trademark rights for 10 countries from Proview International Holdings Ltd. in 2009. But Proview says that the trademark rights, which Apple purchased for £35,000, do not apply to mainland China. The electronics company, which manufactured a computer known as the Internet Personal Access Device (iPAD), is now seeking to ban all imports, exports and sales of the Apple iPad in China.

A court in the southern Chinese city of Shenzen sided with Proview last week, ruling that Apple’s trademark rights extend only to Taiwan, but an appeals hearing is pending. This week, the battle moves to a court in Shanghai, China’s largest city by population. A ban on iPad sales in Shanghai would be especially damaging, as it is home to three of Apple’s five Chinese stores.

Some sources speculate that this is a last-ditch attempt to save Proview, which was suspended from trading on the Hong Kong stock exchange in 2010 due to financial troubles.  The company is reportedly seeking up to $2 billion from Apple.

Read more on the story at Reuters.