How to reinstall Windows without reactivating
Need to format your hard drive and reinstall XP, and don't want to have to go through the product activation process again? You can save the activation status info and then restore it after you reinstall the operating system, as long as you haven't made any changes to the hardware. Here's how:
Before reformatting, in My Computer, double click the drive letter on which you installed XP, and navigate to WINDOWS\System32.
Click "Show the contents of this folder" if necessary.
Copy the following files to a floppy, USB drive, CD/DVD or network location: wpa.dbl and wpa.bak.
After reformatting and reinstalling XP, select NO when asked if you want to activate Windows now.
Restart in Safe Mode.
In My Computer, open the WINDOWS\System32 folder and rename the existing wpa.dbl and wpa.bak files (if you have them).
Now copy your old wpa.dbl and wpa.bak files to the System32 folder.
Restart and you should not be requested to activate again. This only works when you reinstall Windows on the same computer and the hardware remains the same.
Can't play your WMA file?
If you get a message that says “A security upgrade is required to play this file” when you try to play a WMA file in Windows Media Player: This happens when you try to play copy protected content in Windows Media Player 10. If you click the "yes" button, you will probably get a message that says "This computer is not authorized to play this song. In order to play this song you must first purchase it. If you already own the song, sign in to listen to it." At that point, you're given two choices: buy the song for $.99 or click the "I already own this song button." If you click the latter, you may be asked to install the MSN Music Assistant and the digital rights management components on your XP computer may be upgraded by creating a unique identifier and sending it to the MSN server. To download the Assistant, you'll have to sign into MSN with a Passport or Windows Live ID.
If you get a message that you're unable to upgrade the DRM components, it may be because your LAN settings in Internet Explorer are configured to automatically detect a proxy server. To fix that, click Tools | Internet Options, click the Connections tab and then click the LAN Settings button. In the dialog box, uncheck the box labeled Automatically Detect Settings.
Slow Performance of Favorites menu with SP2
If you find that your computer is slowing down to a crawl whenever you try to access the Favorites menu in IE or Windows Explorer after you installed Service Pack 2, it may be because you're redirecting the My Documents folder to a non-local (network) location and have enabled the desktop.ini cache. There is a hotfix available for this problem, but Microsoft recommends you apply it only if severely affected. Read more in KB article 898612.
Memory leak in Tablet PC
If your portable computer is running the Tablet PC edition of Windows XP and you're noticing a gradual decrease in available system memory that causes a performance hit, you may be suffering from a known memory leak caused by the tcserver.exe service. Restarting the computer fixes the problem temporarily, but now there is a hotfix you can get from Microsoft Product Support Services. To find out how, see KB article 895953.
You get an error message when you try to open User Accounts in Control Panel
If you try to open the User Accounts applet in the Windows XP Control Panel and instead of opening, it gives you a message that says "Microsoft HMTL Application host has encountered a problem and needs to close," you can usually remedy the problem quickly by registering a DLL. For instructions on how to do so, see KB article 919751.