If I see a person posting a video of a song, and after this I immediately close this video, but I heard this song because of him, so have I thus shown pleasure for his sin and do I carry his sins? Or if I sin and repent but, for example, I talked with a girl in private and she told me something and after this I repent, but because she gave me knowledge about something, I go to the such-and-such shop to buy something or do something else, does this invalidate repentance, or is it a condition for repentance to leave all the consequences of sins?

All perfect praise be to Allah, the Lord of the worlds. I testify that there is none worthy of worship except Allah and that Muhammad is His slave and Messenger.

Your question is somewhat ambiguous.

In any case, if the video contains some forbidden songs, then whoever posts it is sinful. If you closed that video, then you did well and you will be rewarded for it. If later on you listen to it again or to another music video, then you are sinful for doing so.

As for your statement: Will I bear the sins of that person? Then it does not appear to us that you have done something that makes you bear his sins.

If you spoke with this girl in a sinful manner, and you sincerely repent from this, then your repentance is valid. Her telling you about the shop and you going there does not affect this repentance, as this does not negate repentance.

Finally, we draw your attention to the fact that we have noticed some kind of in-depth questioning that is not pleasing from you. So we hope that you would be cautious about this in the future, as this may lead you to become overwhelmed by difficulty or may lead you to unpleasant consequences.

Allah knows best.