Does your PC have all the minimum requirements?
A PC with a 1GHz Intel or AMD processor
Playing videos purchased on the iTunes Store requires an Intel Pentium D or faster processor
Playing HD-quality videos purchased on the iTunes Store requires a 2.0GHz Intel Core 2 Duo or faster processor
512MB of RAM; 1GB is required to play HD-quality videos
A DirectX 9.0-compatible video card with 32MB of video RAM; 64MB recommended
A QuickTime-compatible audio card
A broadband Internet connection to use the iTunes Store
An iTunes-compatible CD or DVD recorder to create audio CDs, MP3 CDs, or back-up CDs or DVDs
Windows XP Service Pack 2 or later, or 32-bit editions of Windows Vista
64-bit editions of Windows Vista require the iTunes 8 64-bit installer
QuickTime 7.5.5 or later is required (included)
200MB of available disk space
Screen reader support requires Window-Eyes 7.0 or later; for information about accessibility in iTunes, visit www.apple.com/accessibility
Perhaps try the direct download link http://www.apple.com/itunes/download/
Edited by rowal5555, 20 September 2008 - 06:31 PM.