How to change video formats to another format?

i have a video with a .mkv extension but when i try to play/convert it says it cant do it because it has a .0 in the name. now the .0 doesnt show up on the file but under properties it will show up but there are no options to change it. any suggestions for how i can fix it|||use a video converter site such as ivdo.ws or the software Videora, you can change the format into .avi, .mpeg, anything. hoped this helped