iMac won't open all apps and acting weird before this.

[s3o0d]

so yesterday i noticed that when i right click it doesn't give me the "Open with" any more, it says " N152" so i thought that was weird, then i downloaded VirusBarrier and as it was scanning. i opened an software update but it wouldnt open, then VirusBarrier froze and then i rebooted my imac, after that it wont open ANY APPLICATION. NOT EVEN SYSTEM PREFERENCE. so i reset the pram and still wont open apps. then i booted with safe mode and now i can open applications. what should i do now so i can open applications using normal booting. oh and i think i lost the system cd thing that comes with the mac.

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oh oops i posted in Mac pro by accident. how do i move it?

 

[Schtumple]

I doubt you have any malware, so remove virus barrier.

What version on OSX do you have on your mac?

 

[simsaladimbamba]

so yesterday i noticed that when i right click it doesn't give me the "Open with" any more, it says " N152" so i thought that was weird, then i downloaded VirusBarrier and as it was scanning.

Did this thread give you the idea of using VirusBarrier?
Do you suspect any kind of malware, due to your downloading and installing habits?

There are currently no viruses for Mac OS X in public circulation, only a handful of trojans and other malware, which have to be installed manually via entering the administrator password.
The only anti-virus you need to protect your Mac is education and common sense.
Also know, that the term "virus" is often used to refer to other kinds of malware, but there are differences, which you can find out by reading the following:
Mac Virus/Malware Info by GGJstudios​

i opened an software update but it wouldnt open, then VirusBarrier froze and then i rebooted my imac, after that it wont open ANY APPLICATION. NOT EVEN SYSTEM PREFERENCE. so i reset the pram and still wont open apps. then i booted with safe mode and now i can open applications. what should i do now so i can open applications using normal booting. oh and i think i lost the system cd thing that comes with the mac.

Can you create another admin account while in Safe Mode and see, if the same problems occur there?
And do you have a backup of your personal data and system, you can use in the worst case scenario?

Maybe some of these steps can help too:

Mac doesn't boot

Resolve startup issues and perform disk maintenance with Disk Utility and fsck

Troubleshooting: My computer won't turn on

A flashing question mark appears when you start your Mac​

oh oops i posted in Mac pro by accident. how do i move it?

You can use the

button to ask a mode to move the thread, though I already did that, as that is software related and not hardware related as it seems.

PS: What Mac OS X version do you use?