All Mac apps deleted

[goodknighte1234]

Hi there
I was recently downloading a program (Wolfram Mathematica) on my MacBook (OSX 10.4). During the installation process, all of the application files from my mac were erased. I have run Stellar Phoenix, and it wasn't able to locate them. Has this happened to anyone before? Is this the product of a virus or my computer dying (it is 5 years old)?
Thanks!

 

[simsaladimbamba]

Can you make a screenshot of your Applications folder (Finder > Go > Applications or Finder > CMD+SHIFT+A) and attach it to your next post?

And it is NOT a virus:
Currently there are zero viruses affecting Mac OS X in public circulation, but there are other kinds of malware existing, that can infect your Mac.
But as long as you don't install software from unknown and untrusted sources, you are safe, as malware needs administrative permissions to run successfully, which means, you need to install the malware yourself, it can't install itself (one of the reasons, why a Mac OS X virus hasn't appeared yet).
To learn more about malware in Mac OS X and what steps can be taken to protect yourself, read the following F.A.Q.:

Mac Virus/Malware Info by GGJstudios
The above F.A.Q. includes the following topics:

• Malware terminology - What is the difference between viruses, worms, and Trojans?
• Antivirus apps
• What security steps should I take?
• What about sending files to Windows users?
• Why am I being redirected to other sites?
• Recent threats in the news

​

 

[McGiord]

Where you downloaded it from?

That is very unusual. Create another user account in System Preferences, then see if the new user has all the apps?

Any backups?

 

[goodknighte1234]

Here is a link to a screenshot of my applications folder:
http://imgur.com/zqTuc

There used to be many more applications in there, and the ones that are there now don't do anything when I click them.

I can't create a new user account in system preferences, when I click the icon on the dock a question mark comes up and nothing happens. That happens when I try to open any program, so my computer is pretty much useless at this point in time.