Firstly Go to www.apple.com and Select iTunes >Download iTunes.
after that Select your system type and Click on "Download Now" option. Open the file and install it after downloaded in your system.
it need more help follow Apple Support Number .
Click start all programs navigate to iTunes right click select send to desktop to make short cut , or pin to task bar might be another option depending on your operating system.
or you might download iTunes and Quick time again. Enter http://www.apple.com/itunes in your address bar or conduct a search for "iTunes download" to find the link. Click on the iTunes free download link. It is located on the right side of the page. This will take you to the main download page for iTunes software. Enter your email address and then click the box that is labeled "Download Now." This will bring up a box that asks if you would like to run or save the program. Click whichever you like, but by clicking "run," the process will start automatically. After the download is complete, click "run" again, as this will start the installation process. If you have opted to save the program first, locate it in the directory you have chosen and double-click on the iTunes setup program. Follow the installation prompts, including accepting the terms and conditions and indicating where you would like the directory to be created. Continue to follow the steps included with the setup assistant. This will allow you to customize the options, including assigning certain properties to files. You can play all your MP3s through the iTunes interface or set iTunes as your default audio player. Installing QuickTime Go to http://www.apple.com and click the "Downloads" item on the top menu bar. You will then have the option of installing QuickTime. This program allows you to watch streaming video on the Internet, as well as play other multimedia files, such as .AVI files. Click the "Download" button beneath the QuickTime logo. This action will take you to the main QuickTime download screen, where you will be prompted to enter your email address and continue on by clicking "Free Download Now." Repeat steps 3, 4 and 5 from above to install QuickTime on your computer. Be sure to read the information in each box carefully and accept the terms and conditions of use. Version 11.0.2 Added on 02/20/2013 Manage your music and movie libraries on your PC, iPod or iPhone. http://download.cnet.com/apple-itunes/3000-2141_4-10235268.html b> b> Play MPEG-4 movies with AAC sound with latest version of Apple's premier media player. http://download.cnet.com/apple-quicktime/3000-2139_4-10002208.html