Unknown msert[1].exe download message (again).

Hello. Several weeks ago, I had experienced an unusual thing happen involving a random download notification from norton related to a download I had downloaded several days prior. You can read the details here.

http://community.norton.com/t5/Norton-Internet-Security-Norton/Please-help-Unknown-msert-1-exe-download-message/m-p/838866

Well, it happened again. This time it happened while no one was logged on. I looked into it and it looked like it had before. I checked out the file named msert[1].exe and I found two similar looking files called msert[2].exe and msert[3].exe. I checked out msert[3].exe and a download notification from popped up, telling me it was safe.

Here’s what really concerns me though. I checked out msert[1].exe to see if it was legit, but I couldn’t find anything connecting it to Microsoft. I scanned it with norton, and it said there was nothing suspicious. But when I tried to run it, the computer said it didn’t have a valid digital signature. So I just went ahead and deleted it. Is there anything dangerous about what’s been going on and what should I do? Thanks.