Cannot install iTunes because of Bad Image error about ASL.dll

iTunes.exe - Bad Image
"C:\Program Files (x86)\Common Files\Apple\Apple Application Support\ASL.dll is either not designed to run on Windows or it contains an error. Try installing the program again using the original installation media or contact your system administrator or the software vendor for support."

The issue here is not that your iTunes has failed to install properly, but rather that there's a problem with your *Apple Application Support.* (iTunes 9.0.2.25 needs a properly-functioning Apple Application Support in order to work correctly.)

So the best way to proceed is to uninstall both Apple Application Support and iTunes (instead of just iTunes) and then reinstall iTunes (which should reinstall Apple Application Support). We'll also take a few additional explicit precautions along the way (given that it isn't obvious why the ASL.dll got damaged on your system).

The following instructions are for a 64-bit operating system.

Preliminaries

Download and save a fresh iTunes installer (iTunes64Setup.exe) to your hard drive. (Don't run the install on line and don't start the iTunes install just yet.)

http://www.apple.com/itunes/download/

Now, quit QuickTime (if you have that open) and Safari 4.0.4 (if you have that installed and open). Both applications use Apple Application Support, and they will interfere with the uninstall if you have them open.

*Uninstall phase*
Head into your "Uninstall a Program" control panel. Uninstall iTunes. Uninstall Apple Application Support.

(From this point on until we reinstall Apple Application Support, neither QuickTime nor Safari 4.0.4 will be able to run.)

Next we'll remove any leftover program files and folders.

(1) Open "Local Disk (C:)" or whichever drive your program files are stored on.
(2) Open the "Program Files" folder.
(3) Right-click on the iTunes folder (if it still exists) and select "Delete".
(4) Go back into "Local Disk (C:)" or whichever drive your program files are stored on.
(5) Open the "Program Files (x86)" folder.
(6) Right-click on the iTunes folder (if it still exists) and select "Delete".
(7) *Staying in "Program Files (x86)",* open the "Common files" folder.
(8) Open the "Apple" folder.
(9) Right-click on the *Apple Application Support* folder (if it still exists) and select "Delete".

Now empty your Recycle Bin and restart the PC.

*Reinstall Phase*

After the PC restarts, do not open any other applications. Disconnect from your network and/or the internet. Switch off all your security software (firewall, antivirus and antispyware).

Now start the install by doubleclicking the iTunes64Setup.exe file you downloaded earlier.

Reenable all security software prior to reconnecting to your network and/or the internet.

Did the install seem to go through okay? If so, does iTunes start launching properly again?

🙂 Excellent news, jd. Glad you're up and running again.