Search your system32 (if you're 32bit)/sysWOW64 (if you're 64bit) for COMDLG32.OCX, if not, download it from google, place in system32 (if you're 32bit)/sysWOW64 (if you're 64bit), then register it via Command Prompt (running in Admin).
Using the command regsvr32 COMDLG32.OCX