As I understood, you are getting a p3core.dll when you are running Bus Driver game. Provide us with the information to assist you further.
1. Did you make any changes on the computer prior to the issue?
2. Is the issue confined to a game?
I would suggest you to follow the below methods and check if it helps.
Test the issue in clean boot.
How to troubleshoot a problem by performing a clean boot in Windows Vista or in Windows 7 How to perform a clean boot to troubleshoot a problem in Windows Vista or Windows 7
Note: After trouble shooting put the computer to start as usual by performing step 7 from the above Knowledge Base article.
You may run System File Checker scan to fix the corrupted files.
How to use the System File Checker tool to troubleshoot missing or corrupted system files on Windows Vista or on Windows 7 Use the System File Checker tool to troubleshoot missing or corrupted system files on Windows Vista or on Windows 7
Please perform these recommended steps and post if you are still experiencing the issue. I would be glad to assist you further.