Just wondering on what DVD did you use to reinstall Windows 7 Home Premium 64-bit? If it is a Lenovo supplied DVD or a Recovery Partition then the needed Drivers
should be all there.
If Lenovo did not give you a Drivers' Disk when you purchased the Computer then you should ask Lenovo to furnish you with one now.
Most of the the troubles after reinstallation stem for want of Drivers. I think it should be made mandatory upon the vendor to furnish a Drivers' disk when a computer is purchased.