iTunes and Windows Error 1721

OK so I just bought an iPod and it requires iTunes in order to put music on it. I downloaded the iTunes and Quicktime package but during the install I get the Windows 1721 error stating:

"There is a problem with this Windows Installer package. A program required for this install to complete could not be run. Contact your support personnel or package vendor."

After the install, I can open quicktime with no problem but when I try to open iTunes, it shows that its on under system processes (when i alt+tab+delete) but it doesn't turn on on the screen or in the tray. I tried a few solutions online to no luck. I talked to one guy and he said that I might be missing some system files?

This seemed far-fetched but I bought my computer at a small private computer store about a few ago, and after installing the latest windows update, I am getting the "windows isn't genuine" thing popping up.

Anything I can do to fix this? Because I would really like to get my iPod working. Thanks.

Running: Windows XP Professional Version 2002 SP3

PS: I didn't receive a Windows CD when I bought the computer, as the guy who sold it to me stated that it was just one of this 'one-time' XP installs.

 

Try this link http://support.apple.com/kb/HT1926?viewlocale=en_US and follow the

Clean up iTunes installer files on the computer

about half way down the page.