Thank you for visiting the Microsoft Answers Community.
There are a few items that could cause the issue that you are experiencing.
Compatibility, Network, Video are the areas that you need to be concerned with. On Perfect World Entertainment's website, I was able to locate the troubleshooting for their games for each of these areas as well as over simple troubleshooting steps for running
their games successfully on Windows 7.
Please visit their website for information on all of these areas. Then go to Technical Support on the left navigation pane.