As the installed version is someone else's and you don't have account details it will have to be uninstalled and then you can start all over with a new online account and purchase whatever you need..
But first you will have to clean the machine of malware.
What operating system and service pack is installed? You can usually get that information by right-clicking My Computer (XP) or Computer (Vista/Windows 7) and selecting Properties in the drop-down menu. The system properties page will open. Post what it says about the operating system and service pack if any.
It may be possible to obtain internet access in "Safe Mode with Networking:" which is one of the menu choices you should get when clicking F8 repeatedly while booting up.
If you can obtain internet access that way then download, install update and run THIS tool - all in that Safe Mode. Let it remove anything it finds and reboot when asked to.
Run it again in regular mode to see if it detects anything else and if not then you could go to McAfee.com and get whatever software you want.
First enable Windows Firewall then do the following:
1. Uninstall all McAfee programs through "Add or Remove Programs" in Windows "Control Panel".
2. Use the MCPR tool, see this article: How to remove supported McAfee consumer products using the McAfee Consumer Products Removal tool (MCPR.exe). This will remove all McAfee remnants from your computer. (You must have Windows 7, Vista, XP or 2000, SP4 to use this tool)
3. Launch Windows Explorer and delete all McAfee files in "Program Files" but especially in "C:\Document and Settings\<user>\Application Data" and "C:\Document and Settings\All Users\Application Data". You have to set Windows Explorer to show all hidden files and folders (Tools > Folder Options > View tab). Just delete the McAfee folders even if they are empty in all the "Application Data" folders. Can be more than one!
In Vista: C:\Program Files, C:\ProgramData and C:\Users\yourname\AppData\Roaming
If you can't find these files don't worry. It just means that MCPR has done its job.
4. Reboot and redownload/reinstall your McAfee products directly from your account at the McAfee web site.
I am unable to connect to the internet, either way, regular or in safe mode. I am also unable to remove the Mcafee software as it has been disabled and it will not allow me to disable that function. It will not even open the add/remove programs icon.
Well all I can suggest is either our Moderator Secured2k's BootCD- if you have access to a clean machine that can burn media such as CDRW or DVDRW.
Any questions about it must go in that thread.
Or a format and reinstallation of your entire operating system, whatever it is. Make sure you update it immediately.
Our Virus Removal Service wont be able to help you in this case without ability to access the machine.