Windows Live Movie Maker is making my videos look pixelated but Windows Media Player plays them perfectly.

I filmed a vlog on my Sony CyberShot WX80 1080 16.2 MP point and shoot digital camera. It records in AVCHD format at 1440x1080 or 1920x1080 if you choose that setting. The current video I am trying to edit is in 1440x1080. It takes a SDXC card. I am using a 64GB Sandisk brand SDXC. I instert the card and play the videos on Media Player and they look amazing. When I open the file in Movie Maker In the preview screen it looks pixelated and awful. I saved it anyway in case it was just the playback messing up and it wasn't, it saved the same way with pixilation and lag. I converted from AVCHD to MP4 and to WMV formats and it did the same just made it even blurrier. I tried to lessen the quality to 720p but that made it look blurry and worst. I need help please. I am so confused. Thank you.  Also I tried saving it under a custom setting to the video size of 1440x1080 to no avail. It made the video smaller on screen but still pixelated.