I tried to upgrade to 3.5.2 and get internal error 2908 and error 1935 on W7 x86.
I have uninstalled 3.4, deleted all entries in registry relating libreoffice and openoffice, changed to administration user, changed msconfig to start w/o services and startup processes (had to manually start Windows Installer), but always the same result.
I also downloaded from different sources (LibreOffice.com and Chip.de)
Please help
I did the search: http://user.services.openoffice.org/en/forum/viewtopic.php?p=3839#p3839 and followed discussion gives you a step by step solution!
With some more detailed information it would be much more easy to help you. 3.4.what? 64Bit? Might be Bug 46519 - embedded VC++ runtime install fails (error code 1935) or Bug 36677 - Uninstall Problems with MSI on Windows 7 64bit. Try 3.4.5 (or 3.4.6 (I did not test 3.4.6)) or an uninstall tool to delete all parts of 3.4.4 before you install a LibO 3.5