Entry point errors can usually be fixed by deleting the offending dll, then repairing the component it is part of from the programs and features control panel. SQLite3.dll is part of Apple Application Support and can normally be found in
C:\Program Files\Common Files\Apple\Apple Application Support or
C:\Program Files (x86)\Common Files\Apple\Apple Application Support.
Like it or not when installers produce the wrong results the standard operating procedure is to uninstall all of the related software components and start again. Over the years I've had to do this with various products from Microsoft, Symantec, and Apple, to name but a few. I've had an installation of Microsoft Office fail so badly that nothing short of a Windows reinstall was able to fix it despite direct attention from Microsoft's own engineers. Since Apple clearly don't make their installer clever enough to test for and automatically remove any vestige of a previous installation and then drive through the current one regardless of whatever issues might cause a problem (AV interference, missing/incorrect security permissions in the file system or registry, incompatibility with third party software, etc.) your choices are either to try the standard approach, or wait in the probably forlorn hope that the next version of the installer might fare better on a system that is already compromised.
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.
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 QuickTime or 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.
If the issue persists and you have a 64-bit system try the for older video cards version which is a 64-bit installer for mostly 32-bit code, similar to all 64-bit versions of iTunes up to 12.1.
If you've tried the above without success then see the method in Install missing components. What component fails to install, and what error message does it give? See this post for steps to produce detailed logs of the installation which may reveal why iTunes won't install. Look for words like failed or error.
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