Screen recordings

I needed some video clips off some old CD-ROMs. We had had the CD-ROMs programmed by outside vendors years ago and no longer had any of the original source media. I used Articulate Replay to record both the activity on the screen and the audio that went along with it (I used a mic next to one of my freestanding speakers to record the audio). The video on the original CD-ROM was small (about 3.5" x 3.5"). When I viewed the recording in Articulate Replay, it was perfect. However, when I attempted to insert the file as a video clip in a Powerpoint presentation, I wanted to enlarge it to about twice its original size. The result was a very "jerky" video, with the screen activity and the audio not staying in sync. How can I get around this problem?

Kathy