Sudden erratic behaviour from your PC isn’t entirely unusual if you recently installed Windows XP Service Pack 2. Here’s how to put Media Player straight, restore your firewall and generally make your system behave again

  • After I install SP2 some games or other programs don’t seem to work.

    This seems to be a fairly common complaint. It may be due to the fact that, to work correctly, some programs and games must receive information over the internet. This data enters your computer through an inbound port. By default, SP2 enables the Windows firewall. This may prevent the program from receiving the info it requires.

    So tell the firewall to open the port. If you get a security alert message when you try to start the program, click ‘Unblock this program’ then hit okay. In future the firewall will allow the port to be opened when you launch the program.

  • After installing SP2, Nero version appears to be broken.
    Download and install the latest update (version from Nero at

  • SP2 fails to recognise my third-party firewall. Turning off the Windows firewall in the Security Center produces a message telling me
    that I don’t have a firewall.

    This can usually be fixed by visiting your firewall provider’s website and updating to the latest version. Most major firewall providers have now ensured that their software will be detected by SP2.

  • I have not yet installed the first Service Pack (SP1). I’m unsure as to whether this must be present before I install SP2.

    SP2 contains all the updates and fixes previously contained in SP1, so there’s no need to install both Service Packs. SP2 will do the job on its own.

  • Following installation of SP2, my computer fails to start.

    This can happen if you install SP2 on a computer with a Prescott CPU and certain chipsets. Motherboards that appear to be affected are: Albatron PX865 PE Pro, Shuttle SB61G2, Jetway i875P, Soyo P4I865P, AOpen AX4SG Max, Asus P4P800-E Deluxe, Abit IS7-V and Foxconn 865A01-G-6EKRS.
    The problem can be solved with a workaround or a Bios update. There isn’t space here to provide instructions, but you can find a complete walkthrough at

  • Windows Media Player doesn’t work properly after SP2 is installed. I have trouble playing music tracks from within the player, although when I click on a music file in a folder on my hard drive the player opens and works normally.

    This can happen if you are using WMP 9.0. The solution is to download version 10.0, available online at

  • After installing SP2 I get the following message when clicking on an audio file to play it: ‘The Audio Codec identified by the format tag 55 is required to play this file. To determine if this codec is available to download from the web, click Web Help’.

    Format tags, such as tag 55, are used by Windows Media Player to identify which decoder to use to play back your music file. If you get this error message then the MP3 decoder on your computer has become corrupted or damaged in some way and needs to be replaced.

    Here’s how to fix this problem on a PC running Windows XP and WMP 9.0. From the Start menu, click Search. Under ‘What do you want to search for?’ select ‘All files and folders’. Under ‘All or part of the filename’, type l3codeca.acm. Click Search. When the results are displayed, right-click the file and then choose Rename. Rename the file l3codeca.bak. Open Windows Media Player. From the Help menu, select ‘Check for Updates’. An up-to-date version of l3codeca.acm will be installed on your computer.

  • I want to turn off the ‘enabled by default’ pop-up blocker that SP2 installs in Internet Explorer.

    You can do this from the pop-up notification bar’s Context menu. If you have the toolbar turned off, click Tools, Pop-up Blocker or Tools, Options and select the Privacy tab. Deselect the Block Pop-ups checkbox at the bottom of the dialog box.

  • The Windows Security Center says that the status of my Norton security product is ‘unknown’.

    Norton Security products contain a tamper protection feature that prevents malicious code from determining their status. This feature also prevents Windows from determining the status of the software. Symantec will provide a live update that will correct this problem. The download should be available by the time you read this.

  • Since installing SP2 I can no longer open attachments in Outlook Express.

    This configuration change prevents access to files attached to newsgroups or emails that could contain viruses. You can turn this feature off by going to Tools, Options and clicking the Security tab. Uncheck the option entitled ‘Do not allow attachments to be saved or opened that could contain a virus’. Click ok and view the email again. Any attachments should now be available as normal.

  • Windows Messenger 4.7 included in SP2 does not support the MSN Add-in.

    This change is designed to improve security. Windows Messenger 4.7.3000 no longer supports the MSN Add-in. In order to continue using the add-in you’ll have to downgrade to Windows Messenger 4.7.2009. Go to

  • After installing SP2 my computer seems to run more slowly than before.

    When SP2 is installed it replaces the majority of the existing operating system’s files. On completion the file placement on the hard drive may not be ideal for optimal performance. Defragmenting the hard drive should do the trick. Go to Start, All Programs, Accessories, System Tools, Disk Defragmenter.

  • In Internet Explorer I click on a hyperlink to access a video file but, instead of opening in Windows Media Player, the file is opened as text in my browser window.

    This problem occurs if Internet Explorer is not set to open a file based on its actual content and uses an incorrect content identifier sent by the website concerned. You need to alter the default setting. In Internet Explorer go to Tools, Internet Options and click on the Security tab.

    Select Internet Zone and select the custom level button. Scroll down to ‘Open file based on its content rather than file extension’ and ensure that the option is enabled. There’s a security risk associated with this action and you should only do it if you have the problem outlined.