Have no remote for the device.so i have been playing movies manually! how can i take off the captions.

Normally when a DVD is inserted, the subtitles option (if it appears in the on-screen DVD menu) is set to 'OFF' by default, but since you do not have the remote, you cannot access it. Some DVDs have the subtitle/captions enabled at startup, so there is nothing you do can do without the correct remote for this model (which may no longer be available anywhere) and it's even worse if the subtitles are not in English or the audio language is not English or both!

Nice to have a remote (universal one if you can find one which can operate this model) then you can have basic control over it, but I cannot assure you that it will turn subtitle/captions off per disc. Just one of those things - but you can look around for a universal remote (if it has subtitle button) and it might work. Or you can look around at secondhand remote/DVD decks online etc.

Up to you what you decide to do here. If it comes to the crunch, and you can no longer tolerate the subtitles being on all the time with each disc during manual playback, consider replacing the whole player (this is cheaper in the long term) - but only as a last resort, since Blu-Ray players (with DVD playback support) are becoming cheaper to buy. Something to think about later on if necessary.