How to identify which "program/s" associate with "Run As"??

I'm still using Windows XP Pro and had been fine until about two days ago.
I have this "Run As" Pop up asking me to run a unknown program with a particular user account/s a few days ago, and I just couldn't find out which program/application has triggered it. I had tried to locate the unknown application via the Task Manager's Application menu, but it indicated nothing at all. It was just blank!! There are quite a few applications starting up at my Window's start -up Menu under Task Manager, but I do not know which one was causing it. Since I have no recollection of which particular NEW application/s have been triggered/installed a few days ago that would trigger this "Run As" Pop up, that is why I'm asking for help here!!!!!!

What's name of unknown program?

Do search of drives for it and see which Program Files it appears under:

Thank you for replying! The problem is that there is absolutely NO indications of what and where this program has been installed in my windows for triggering this "Run As" prompt. Not even in the Application Menu under my Task Manager, which I would have thought it might indicate in it! Basically, I only got the "Run As" prompt but no indication what so ever what and where the program triggering it may be! However I may consider to use the "Restore" command as my last resort to restore back to the latest working system state if I could not resolve it!!!!

If I was guessing then I would assume it could be some malware trying to get elevated rights to attack your system. I would start by running MSCONFIG and looking to see what is in startup - if there is something you don't recognise then try disabling it and seeing if the run as goes away. If it doesn't then try turning off recognised programs - hopefully you will find which one it is by trial and error.

PS - don't forget to turn them back on again.

Post deleted by cheshire_man

Not sure about XP as i no longer have an XP system. I wonder if there's a branch in the registry on XP called OpenWithList with sub-branches showing the various programs. Perhaps do a search with Regedit for either open with or openwith.

I did try "Ccleaner" latest version! Under its "tools" and then "startup", it identified various list of programs starting up at my windows bootup times, however, I just couldn't recognize which is the CULPRIT and therefore couldn't disable it. At the moment I just click the "OK" button under the Run As prompt to remove it from my screen. It is a bit incontinent but I could live with that so far!!!!