Error code 0x8007042c is translates to "The dependency service or group failed to start" and is a Windows error message.
You haven't said whether you've got a problem connecting to the internet, but I would guess you might have.
What is your operating system - is it Windows Vista by any chance?
What is the software you have installed - you say, "since I install this software" - what software?
The answer to this question depends on which service is affected, and what your OS is. It's a known problem with one of several solutions, and the Microsoft forums have several threads on this subject.
If your question is not related to a McAfee product, you would be better off asking it on one of the Microsoft forums -
http://technet.microsoft.com/en-us/windows/cc468658.aspx has options for Win7, Vista, and XP.
You might find the answer in one of these threads -
If not, you'll have to give some more information to whoever tries to answer you so that the problem can be properly identified.