Hello Jatin Bumbra,
I suggest you uninstall your software that made registry changes to your system for Connection Settings.
Without knowing the software name, we have no idea what has changed or is being blocked.
Do you see any new programs that show up when you go to All Programs?
You might be able to go into the event viewer and see when you installed the program in the application or system event logs.
You can find and launch Event Viewer by opening the Control Panel, accessing the System and Security category, selecting the Administrative Tools item, and double-clicking the Event Viewer icon. However, you can also simply click the Start button, type Event in the Start Search box, and press Enter once Event Viewer appears and the top of the results display.
Once you have identified the software that was loaded, then you can uninstall it. If you have problems uninstalling it, use the Automatic Fixit for Uninstall programs. Click here for the link to download.
If you continue to have problems with McAfee, you can uninstall it using the McAfee removal tool otherwise, it will leave strings in the registry.
You can download any antivirus you like to be protected. If you want to use Microsoft Security Essentials, you can download it from here. It is a free real-time antivirus.
Let us know if this helps.
Marilyn