WSUS 3.0 Install/Uninstall/Repair

I have update to WSUS 3.0 and i was getting "Not able to connect" and "Service could not start" errors. I have tried reinstalling Windows Internal Database and WSUS but i was not able to. I have tried uninstalling WSUS 3 , reinstalling WSUS 2 and upgrade to 3.0 but then now i am getting an error message saying "Command-line parameters not valid". Below are the error code i have come across in WSUSSetup.log:
Error 0x80070002: The system cannot find the file specified
Error 0x80070643: Fatal error during installation
ParseCommandLine failed (Error 0x80041453)
I want to know if there is anything i can try out further to get WSUS 3.0 working fine??? Thanks in advance.

I will suggest you to make clean installation of WSUS 2 and then upgrade to WSUS 3. You can try using CCleaner for uninstalling WSUS that might be currently installed and then proceed with installation of WSUS 2, later WSUS 3.