you need to install the security update’ Microsoft Visual C++ 2005 Service Pack 1 Redistributable Package ATL Security Update’ before installing iTunes on your computer.
Let’s follow these steps before you proceed with the installation of ITunes.
- Download and install:
Microsoft Visual C++ 2005 Service Pack 1 Redistributable Package ATL Security Update
- Also, make sure that you have iTunes installer installed on your computer or else download and install it.
- Uninstall all iTunes software from Program and features.
a)Open Programs and Features by clicking the Start button , clicking Control Panel, clicking Programs, and then clicking Programs and Features.
b)Select the program, and then click Uninstall.
**Uninstall or change a program** - **Windows** - Microsoft
4.Reinstall all iTunes software and check if it works.
Removing and reinstalling iTunes, QuickTime, and other software components for Windows Vista or Windows 7
http://support.apple.com/kb/HT1923
For more information refer this link:
http://discussions.apple.com/thread.jspa?threadID=2217499&tstart=0
Trouble installing iTunes or QuickTime for Windows