I was recently downloading a file and accidently clicked cancel about 80% through the file. It was a movie around 700mb, so re-downloading it wasnt an option, since i have capped internet. When i searched for the file again to resume the download, i couldnt find it. With a bit more searching i found that the exact same file was still there, but it had a different file name. Is it possible for me to somehow resume downloading that file to the original file on my computer, so that it resumes from 80%?

yes. Sometimes files do have different names but same download hash (same contents).

exactly; the problem is, if i try to download the same file with a changed name, the download will start from 0% again and i will have to re-download the entire file

Not if it has the identical download hash. If it does it will simply download with a new name. If its download hash is different then it will be seen as a separate file & use create a different separate incomplete file.

so how do i figure out if it has the same download hash? oh wait, thats not the # column which tells you the number of times the file has been downloaded is it?

not sure what you mean. Sounds like the uploads column.

Just choose to download. If not what you want then cancel.