Dear scotty1313
You can download the installers from here:
BitDefender Internet SecurityBitDefender AntivirusTotal Security You have to click on the folder of your country (language). There you can download the installer.
xcomm.dll is part of BitDefender.
For your other issue put in the windows installation cd-rom. Go to start,run,type cmd press enter after that type sfc /scannow and press enter again. Now system file checker will replace or place missing operating system files back.
Best regards
Niels