Hi Chris and Falcon !! Welcome to the forums
@ Falcon : Nice suggestions
@ Chris : Is it the situation from the very beginning , or a recent scenario ? If recent , have you ran any third party disk cum registry cleaner before getting into this trouble ?
Initially yo may try one thing , that is
SFC /SCANNOW Command - System File Checker . It will bring everything to system default .
If SFC scan failed , it is to try a
System Restore with a previous date before the trouble came . And if System restore is also failed , finally it is to try a
Repair Install .
Please post back the results .