Other/additional solutions:
per: http://technicalsupport.businessobje...1%200%20356275
""Error 1500: Another installation is in progress. You must complete that installation before continuing this one."
Why does this error message appear, and how can it be resolved?
Resolution
This error message appears because a registry entry for the Windows Installer is indicating that an install is already in progress. This registry entry must be removed in order to complete the installation.
To remove the registry entry:
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CAUTION:
The following resolution involves editing the registry. Using Registry Editor incorrectly can cause serious problems that may require you to reinstall the Windows operating system. Use Registry Editor at your own risk.
For information about how to edit the registry, view the Changing Keys And Values online Help topic in Registry Editor (Regedit.exe). Note that you should make a backup copy of the registry files (System.dat and User.dat) before you edit the registry.
========================
1. On the task bar click the 'Start' button and then click 'Run'. The 'Run' dialog box appears.
2. Type 'Regedit' without the quotes in the 'Open' box and click 'Ok'. The 'Registry Editor' dialog box appears.
3. Right-click the plus (+) sign to expand each of the folders listed below in the order shown.
HKEY_LOCAL_MACHINE
SOFTWARE
MICROSOFT
WINDOWS
CURRENTVERSION
INSTALLER
4. Under the expanded 'Installer' folder right-click the 'InProgress' entry, and click 'Delete'. The 'Confirm Key Delete' message box appears. Click 'Yes' to delete the entry.
5. Close Registry Editor."
per: http://www.rickrogers.org/fixes.htm#Installation
"Installation Problems:
Try cleaning up the installer. Click start/run, type services.msc and click "ok". Scroll down to "Windows Installer" and double click it. Stop the service if it is running, set the startup type line to disabled. Click apply/ok and reboot.
Delete the contents of the temp folders, there may be a file in there interfering with the setup routine of the installer. Check both:
C:\Windows\temp
C:\Documents and Settings\<username>\local settings\temp
Now reverse the first set of steps and re-enable the Windows Installer (You can just set the startup type to manual). Reboot.
Turn off all other running programs, especially your antivirus software. Use ctrl+shift+escape, if necessary, to "end task" on everything.
Now retry installing some software. If everything goes ok, but you see that it is only installing for certain users, or you are having trouble with limited accounts, please see this page on running software in a WindowsXP environment. You may also find it useful to run the installer cleanup utility:
Description of the Windows Installer CleanUp Utility
http://support.microsoft.com/?kbid=290301
Updating the Windows installer can help as well:
Windows Installer 3.1 (v2) is available
http://support.microsoft.com/?kbid=893803
If it doesn't help, here are some further articles that may:
"Error 1719. The Windows Installer Service Could Not Be Accessed" Error Message When You Try to Add or Remove a Program
http://support.microsoft.com/?kbid=315346
Windows Installer Error 1619 When You Install from NTFS-Protected Directories
http://support.microsoft.com/?kbid=316309
OFF: "The Windows Installer Service Could Not Be Accessed" Error Message When You Try to Install Office
http://support.microsoft.com/?kbid=324516
There is also a known problem documented on systems that have SP2 installed. The fix is downloadable from this article:
Computer stops responding when you try to install an update in Windows XP Service Pack 2
http://support.microsoft.com/?kbid=885894"

