I'm working on a computer that had MSE installed and running at one point. But then something happened and it wouldn't launch on startup. Manually trying to start it threw some error about it needing to be reinstalled. Windows update indicated there was an update for it so I ran Windows Update and it seemed to update properly. Well at least the Malicious Software Removal Tool updated successfully.. The program still would not launch, same error as before. So I manually downloaded it from Microsoft, on trying to install I got an error that it can't find some file (appeared to be a temp file unpackaged by the installer app), I hit Ok, at this point the install quit unsuccessfully. Now I decided that maybe what I downloaded was some upgrade that MS decided I needed (because I used IE9, thought maybe it could tell what I had) rather than a full install. So I thought I'd just uninstall it and reinstall it. When uninstalling I got an error before the typical uninstall window came up. I think it said that it was already uninstalled and did I want to remove it from the list of installed applications. I told it no. I then downloaded and installed Revo Uninstaller and let it do its big scan on it. From there I removed everything related to it. Then I redownloaded it and on the install I get the same dialog that I had before, where it is missing a file. This time I wrote down the file, its looking for mp_ambits.msi. It thinks its in c:\ddc3450.... (so a temp dir). When I hit Ok it says it can't be found and to verify I have access to this location and try again. Or try to find the installation package 'mp_ambits.msi' in a folder from which you can install the product Microsoft Antimalware. I did eset's online scan and came up with nothing, so I don't think there is any malware preventing the installation. Suggestions?