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I installed two antivirus in my system. After the installation my computer continuously going to crash. Why this happen?

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closed as not constructive by random Jul 27 '12 at 16:04

As it currently stands, this question is not a good fit for our Q&A format. We expect answers to be supported by facts, references, or expertise, but this question will likely solicit debate, arguments, polling, or extended discussion. If you feel that this question can be improved and possibly reopened, visit the help center for guidance.If this question can be reworded to fit the rules in the help center, please edit the question.

Just another example of why everyone always says "Never install multiple AV programs." - As for the actual why, who knows. Just boot into safe mode if possible and remove one. – EBGreen Jul 27 '12 at 15:46
I'm not sure if this has something to do with it, but running two real-time antivirus programs simultaneously isn't a very good idea. To be able to answer your question: Which antivirus programs? What exactly happens when the PC crashes? – Dennis Jul 27 '12 at 15:46
As much as they are a necessity, I can't help but think that A/V programs have grown into monsters, which aren't much better than the things they purportedly try to protect us from. – Darth Android Jul 27 '12 at 15:48
i installed avg and quick heal. After the installation my computer shows not responding message for long time – ebinpaulose Jul 27 '12 at 15:51

You did not give enough information to give a complete answer, but consider this:

  • Virusses hide themselves deep in the OS (to avoid detection)
  • If a virus is loaded it can block anti virus software.

The answer from anti virus software is that they delve even deeper into the OS, trying to be the first to be called. Now you install two programs, both fighting to be first. This sometimes leads to problems the one I will describe below.

  • 1 anti virus program installed
  • You try to open a file.
  • The AV program intercepts the file open call, opens the file on its own and scan it for a virus. If no virus is found it allows the original call. If one is found it aborts the file open and displays a warning

Now lets try this two two anti virus programs installed

  • You try to open a file
  • AV1 intercept the call and tries to open the file on its own so it can scan it.
  • AV2 sees something trying to open a call and intercepts the call from AV1.
  • AV1 sees AV2 trying to open and intercepts...
  • AV2 sees AV1 trying to open and intercepts...
  • AV1 sees AV2 trying to open and intercepts...
  • AV2 sees AV1 trying to open and intercepts... ... Welcome to an infinite loop.

This is by no means the only reason why 2 AV programs would result in problems. But it is one easily explained.

Regardless of the cause, the rule of thumb is do not install two AV programs. If you want to install an other AV program, then first remove the old one. Reboot. Then install the new AV.

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