Cannot install Norton

I would suggest that not being able to install it is a good thing, based on the negative reports it gets on these forums. Also McAfee is another anti-virus program, which you also don't need. You don't need one AV program, let alone two.

Search 'do I need anti-virus software on a Mac' on these forums for more advice/comments and this link is a worth reading:

http://www.reedcorner.net/guides/macvirus/

If you still decide you want an AV program, the one that gets the most recommendations for being trouble-free seems to be the free/donationware clamXav: http://www.clamxav.com/download.php

Norton Antivirus has a very long and illustrious reputation for mangling Mac OS X systems, sometimes to the point where a complete reinstall is necessary. Among other things, it installs kernel extensions which are known to cause kernel panics and system freezes; it contains known and documented bugs which can silently corrupt Adobe Photoshop and Adobe InDesign files, destroy a user's ability to authenticate as an administrator, and (on PPC systems) can cause Classic to stop functioning; and Symantec has on at least two occasions now released flawed .dat file updates which erroneously report certain critical Mac OS X files as "viruses." (Deleting these "viruses" causes damage to the system that in some cases renders it unbootable.)

Norton Removal Tool (Symantec Uninstaller):

http://www.symantec.com/business/support/index?page=content&id=TECH103489&locale =en_US

You may find this User Tip on Viruses, Trojan Detection and Removal, as well as general Internet Security and Privacy, useful:

https://discussions.apple.com/docs/DOC-2435

Bear in mind that from April to December 2011 there were only 58 attempted security threats to the Mac - a mere fraction compared to Windows malware:

http://www.f-secure.com/weblog/archives/00002300.html

Marc Meunier wrote:

I am trying to install a fresh copy of Norton but in the process i keep getting a message telling me that i cannot move the install to my DISK because

there is a file of some kind (McAfee Internet Security) keeping me from doing so.

From McAfee -- Instructions for uninstalling Internet Security for Mac:

Steps to uninstall:

1. Click Go from your Finder window.
2. Select Applications.
3. Double-click the McAfee Internet Security Uninstaller.
4. Check the box beside Uninstall SiteAdvisor.
5. Click Continue.
6. Enter your admin password and click OK.
7. Click Finish.