Re: Software For Video Creation.
"I have to create video presentations for my working projects. Could you advise me some programs that will really help?"
You don't mention which OS you are using. Is this a case of "there is only Windows!"?
If not, you can make impressive videos with a soundtrack using the Photos (was iPhoto) app on OSX or an iOS device.
If you are using Linux (or MacOS or Windows) and can cope with a command line you can make videos using ffmpeg which can be used to trim, join, resize, convert formats and convert an image to a video clip. It will add sound to avideo track and it's fast and efficient. Steep learning curve.
 On a 3.4GHz i7 some video operations can be done at 8,000 fps which is impressive. OK these are trivial tasks but seem to be the ones that are done often such as stripping the audio from a file so that you can add your own soundtrack.