Actually, there’s a method of installing RealOne without all the nasties; one explanation is here.
It’s the first method I tried when I realized that MPC didn’t cover everything, but I found it a tad tedious and went with the Real Player 8 anti-spyware installation.
Back in the old days, when the 'net was young and wild and software was created with the blood, sweat and green LED displayed calculations of some adventurous, authentic geeks (circa 1992?), there were plenty of new and exciting software choices available to play new and exciting audio/video file formats on one’s computer. Names like VivoActive and Streambox along with early versions of WinAmp and, yes, RealAudio Player.
But times changed and names like Vivo and Streambox were gobbled up by corporate turncoats like Real “There Can Only Be” One Player. Yet those old software titles are still out there, intact with their wonderously extensive yet simple options.
Badtz Maru, for your audio convert issue, may I suggest: Streambox Ripper v.2.009 (or earlier versions).
You have to physically delete the Message Center executable, or else RealOne will start the message center (and put it back into your startup folder) every time it starts.
Although there are plenty of mpg/mpeg joiner programs out there, even many freeware and shareware, DreadCthulhu’s idea is, IMO, best. If I’m not mistaken, joining mpg/mpeg files with different frame rates would be a problem as would the different video dimensions of video clips. You would end up with a joined file that would be jerky and contain overlap artifacts along with other weird behaviors, assuming it would even play at all.
Just make sure that your player for your newly converted audio mp3s isn’t the same player used for video mpeg/mpg files, otherwise you could end up repeating what happened in the OP, only instead of RealOne it’d be another audio/video player giving your computer user a (surp)rise.