Sorry to hear that iTunes is not installing on your Dell computer. I found an article that will assist you in troubleshooting installing iTunes on Windows:
Thank you for posting in the Apple Support Communities. I hope this helps!
Thanks a lot Sheila!
Unfortunately it didn´t work.
All the "common installation problems" are for Windows Vista or Windows 7.
Although I had the same problem before upgrading to Windows 8 Pro, there are no solutions for this new software.
General installation problems didn´t work either.
I saw in the forum that I am not the only one, but still I can´t find an answer..
Thank you for using the Apple Support Community. Due to the nature of your issue or question you may find more information by using another one of Apple's support resources - https://expresslane.apple.com/GetproductgroupList.action
All the best,