Windows 7: Windows Installer - can't install ANY msi package

Windows Installer crashes any time i try to install an msi. Get the message 'windows installer has stopped working'. I think the version is version 5.0 in Windows 7, but can't download this from anywher to see if reinstalling it helps. Tried to install the old 4.5 version but it won't let me. Help!

Have you tried re-installing the OS? Did this problem occur with a fresh install?

Had this just an hour ago. I was lucky enough to have a recent Acronis backup. Try a system restore point perhaps?

yep, I'm also having this issue, it accord for no reason what so ever. Windows update won't even work. I think it started happening after I tried installing Java. Does anyone have a working fix for this?..

EDIT: sidneysides do you have ccleaner installed?

EDIT 2: It could be ccleaner, maybe it deleted a registry that was needed...

I have the same problem. Is there any solution for this? Also i dont have ccleaner installed.

I've just started getting this exact same problem this morning (build 7000). Event Viewer is helpful as ever with:
I don't have CCcleaner installed.

.NET Framework is ntdll I just recently reinstalled windows 7, and it's working fine now, maybe .NET corrupted.

Yup I am having this problem as well when I try to use "steaminstall.msi". The thing is I had installed steam on my previous 7 install but this time it is not working. If it is something related to .NET then I once tried to install .Net Framework 3.5 SP1 as I wasn't sure if 7 had it already and when I double-clicked "dotnetfxsetup.exe", it doesnt do anything. So could this have corrupted anything? or Ccleaner or GlaryUtilities?

ccleaner I think what did it for me, I think it's a registry issue.

EDIT: I just installed Steam

same here with installer not working for any install. I do not have ccleaner just vanilla Windows 7 ... gonna try rebooting before going for a full on re-install!