Q: how do I download apple software update for windows 7?

You might want to consider starting a new discussion. Since this one is a couple of years old, less people are likely to look at it. A new post would be much more visible. You can link to this one. Try posting in the iTunes for Windows community.

Try repairing Apple Software Update from the programs & features control panel, and then try to update iTunes again.

The branched thread title confused somewhat.

For general advice see Troubleshooting issues with iTunes for Windows updates.

The steps in the second box are a guide to removing everything related to iTunes and then rebuilding it which is often a good starting point unless the symptoms indicate a more specific approach.

The notes below the second box should help with items that still won't uninstall or delete. The Microsoft utility may help with the reinstallation.

Review the other boxes and the list of support documents further down the page in case one of them applies.

The further information area has direct links to the current and recent builds in case you have problems downloading, need to revert to an older version or want to try the iTunes for Windows (64-bit - for older video cards) release as a workaround for installation or performance issues, or compatibility with third party software.

Your library and device backups should be unaffected by these steps but there are links to backup and recovery advice should it be needed.

tt2