"I have tried to open these files but don't know how."
BlueScreenView will show you basic details for previous BSoDs - you can get it from here.
If your BSoDs are all the same (Bug Check 0×116: VIDEO-TDR-ERROR) then the troubleshooting information on this webpage will hopefully help.
"Please let me know what hardware I need to replace.............."
Again, if the BSoDs are all same and your motherboard has onboard graphics (or you have a spare card available) then remove the current card for testing purposes.