File help

hello kirupians =p

well i have multiple dvd files…it is a movie cut up into about 5 files…i would like to make those 5 files into 1 so i can watch it much easier

i also would like to know if there is a way to make the dvd file smaller…mayb make the quality worse by a little bit…that is fine also i do not mind

so can you help me find some programs to let me do this…

i did some research online but it ended up not working plz help =p thank you