bup this and bup that??

Backup file.

("Backup of a data file; created automatically by various applications; generated in case a program crashes or the original file becomes corrupt and needs to be restored.")

BUP files are backup of IFO files, which are the information files that link VOB files together on dvd's. the BUP files are present on the disc in case the original IFO file becomes unreadable, so the dvd can still play if it's scratched

why it would be in your quarantine files? if you downloaded a dvd from p2p the file may have been corrupted, but as BUP files aren't pc or mac executable it's possible that you may have a virus that's set to destroy certain file types, or the person you downloaded from may have had a virus that corrupted the files

i'd suggest run a full and complete scan of your system with up to date anti virus software and double check with windows defender

shall i dlete them all then?

the only thing i downloaded was 3121 the dvd

try burning the dvd to a disc and see if it plays. you can't get a virus by playing a dvd.

many dvd players will play non compliant discs without BUP files. you would need to move the bup files back to the dvd folder to burn them. they should be the same as the .IFO files so you could delete the BUPs and copy and rename the IFO's to the corresponding BUP files and burn them

if the IFO and BUP files are corrupt you can download something like IFOedit and recreate the IFO files to play the VOB files. you will lose the original menu structure but it will play the video files in sequential order which is better than nothing