So you wiped Windows 7 x64 to put Windows 7 x64 back on? Well I can understand that as you get rid of all of the bloatware that systems seem to have on them anymore. So did you make sure that all of your drivers are installed and up to date? Make sure you are running the latest drivers for your GPU and update DX if needed. Even though Windows 7 comes with DX 11 most games still need DX 9 and both versions can be installed with no problems. Check device manager and make sure you are not missing any other drivers for your system.
Alot of laptops will have proprietary drivers that may not be included with a default Windows 7 install. That is were I would start anyway. Good luck.
Also what game were you trying to play?