I know this is a common problem, but as far as I can tell, the common solutions aren't applicable.

My only two source videos are WMVs. My source audio is WMA. I have 36.6 GB of free disk space on my C: drive. I also tried saving it to my D: drive, which has 132 GB of free disk space.

Can anyone help me? I'm using 2.6. Is that just too old? I tried downloading the latest version, but it froze my computer. If I am able to download it, will I be able to open a file made in 2.6? Are there any other possible causes? 

Thank you for your help.