Question : What is QTSTimer?

I just installed the Windows Update files that were released. After I rebooted and when I shut down the computer again, I got a message that QTSTimer was still running (got the "end now" prompt).

What is this and what program is it associated with? I tried Google but there's little info on it.

Answer : What is QTSTimer?

Well then it's not running now.  Wish I could give you a more definitive answer.  The below link is about the best indication that it is related to QuickTime that I could find, although even this one is not 100% positive.
http://techrepublic.com.com/5208-11196-0.html?forumID=53&threadID=188380&messageID=2052985

About all I can recommend at this point is to keep an eye out.  Your system is clean from viruses or ad/spyware, so I don't have to urge you to keep it so.  The file itself is not on your pc, nor are there any references to it in the registry.  

Perhaps next time something uses QuickTime you can check processes again and see if it's there.