Good advice sassofalco
Hi Mathew, this might help. Advice from Windows Live OneCare Online : -

"Installation requirements for Windows Live OneCare

To ensure that your Windows Live OneCare installation runs smoothly, please review the following information:

Step 1. Make sure your computer meets the system requirements for Windows Live OneCare

Check your computer for the following minimum requirements for successful installation. If you are unsure how to find this information, you can start the installation process and Windows Live OneCare will check your system automatically during setup. To install Windows Live OneCare, your computer must be connected to the Internet.

• Microsoft Windows XP (Home Edition, Professional, Media Center Edition, or Tablet PC Edition) with Service Pack 2 (SP2) or later, or Windows Vista 32-bit and 64-bit (Home Basic, Home Premium, Business, or Ultimate) operating system (OneCare does not support the Windows XP Professional 64-bit operating system)
• Microsoft Internet Explorer 6 or higher for Windows XP SP2; Phishing Filter requires Windows Internet Explorer 7
• PC with 300 MHz or faster CPU speed
• 256 MB of RAM and 600 MB of available hard disk space; 25 GB of available space reqiured for central backup features
• 56 kbps or faster Internet connection (broadband recommended)
• CD or DVD burner, external hard drive, or USB-enabled media or storage device required for backup and restore functionality (not required for installing Windows Live OneCare)
• At this time, Windows Live OneCare does not support computers with a Dynamic Disk structure

Step 2. Uninstall other antivirus and firewall programs

This step is very important no matter what brand of protection software you use, because installing one antivirus or firewall program over another on the same computer could potentially lock up the computer.

Windows Live OneCare might not run, or it might slow the performance of your computer, if you install it when other antivirus or firewall programs are also installed on your computer. During setup, Windows Live OneCare checks for common antivirus and firewall programs that are known to conflict with Windows Live OneCare and provides means for you to uninstall them.

Antivirus and firewall programs known to conflict with Windows Live OneCare:

• Symantec Norton Internet Security 2007
• Symantec Norton Antivirus 2007
• Symantec Norton SystemWorks Standard Edition 2007
• Symantec Norton SystemWorks Premier Edition 2007
• McAfee Internet Security Suite 2006
• McAfee Virus Scan 10
• Trend Micro PC-cillin Internet Security 2007

If no programs are listed, or if only Windows Firewall is listed, then you probably do not need to uninstall any programs. If you do find that other antivirus or firewall software is present on your machine, you will need to uninstall it before installing Windows Live OneCare.

During setup, Windows Live OneCare checks for the programs listed above and will notify you to uninstall any that are found. To avoid any potential problems, however, Windows Live OneCare recommends that you uninstall any other antivirus and firewall software (except for Windows Firewall, which is part of the Windows XP operating system and cannot be uninstalled) before beginning Windows Live OneCare installation.

Notes:

• To avoid putting your computer at risk, do not remove pre-existing antivirus or firewall software until you are ready to install Windows Live OneCare.
• You do not need to uninstall Windows Firewall, which is a component of the Windows operating system and cannot be removed. It does not conflict with Windows Live OneCare; in fact, Windows Firewall provides basic firewall protection while you are removing the old software and installing Windows Live OneCare.

Step 3. Make sure you are logged in as an Administrator on your computer

You need to have a user account with administrative privileges on your computer in order to install programs like Windows Live OneCare. To give yourself administrative privileges, you can either log on to the computer with the username "Administrator" (and its password), or use another account that you know has Administrator permissions.

To find out which permissions your user account has:

• Click Start on the Windows taskbar, then click Control Panel.
• Double-click User Accounts. The listings in the Group category will tell you what kind of permissions your current account has.

To learn more about managing Windows user permission levels, click Start on the Windows taskbar, then click Help and Support.Release Notes

Release notes describe late-breaking issues, workarounds, and other important information you should know in order to install and run Windows Live OneCare successfully. Please read this section carefully.

Virtual PC (VPC) compatibility
Windows Live OneCare has not been tested with Virtual PC and is unsupported in VPC environments. Subscribers who choose to install and run Windows Live OneCare on a virtual hard disk do so at their own risk. Behavior and stability is unknown, though intermittent VPC crashes have been reported."


Windows Live OneCare Installation Requirements