UPDATE: There is a similar question, but my question is different because it is very narrow and about a very specific security concern. In short, I used a laptop to make posts on a Russian social network (vk.com) from Japan and am now travelling to Russia with the same laptop. My specific concern is how I can exclude the possibility of being identified, in Russia, as the author of those posts. I am afraid that if I connect my laptop to the Internet in Russia, my laptop might leave some "fingerprints" in Russia coinciding with "fingerprints" I left when I made those posts from Japan. The answer given to the question referred to above does not address my concern at all.
More details are below, in the original text of my question.
I am a Japanese student learning the Russian language and will soon travel to Russia to have a kind of internship or training.
I have a security concern and a background to it. The background is that I actively participated in Internet discussions on the Russian social network vk.com under a fake name and made many provocative posts there, so a number of people explicitly wrote there that they would do their best and utmost to find my real identity and make it public. My posts are definitely of no concern to police and were not even deleted by the admins, but quite a large number of people got really agitated as my posts were about politics, religions, cultures, and similar sensitive stuff and written in a provocative manner. I cannot afford getting my real name publicly associated with those posts, but I did not see how people could find my real name, so I even made some posts saying they would not be able to find my name.
Some time ago one Russian sent me a message telling me he had discovered my real Japanese IP addresses, and he told me some of them. Although I had not used any proxy servers to make my posts, I got shocked, because vk.com is not supposed to share my IP addresses with anyone. The guy then wrote he had been able to find my IP addresses because he works in a Russian company that has access to a lot of data related to the use of the Internet in Russia. He added that he had somehow tried to find my real name based on my Japanese IP addresses, but had not succeeded. Indeed, my Japanese IP addresses do not give any leads, and no Japanese provider will tell my name to Russians.
Now I am travelling to Russia and intend to use there the same laptop I used to make my posts; I will be given an Internet connection in Russia and, in view of what the guy told me, will obviously need to avoid any possibility of leaving any traces in Russia that could link my Russian IP address with my past posts. The reason is that knowing my Russian IP, people might find my real name by contacting my Russian hosts. Ideally, I would like to continue using the same account in the social network to make posts while staying in Russia.
My question is this: What should I do to meet these needs?
I am asking because I know little about such security matters and, in particular, what kind of information is collected from my laptop by Internet providers and servers such as vk.com, so I am afraid to even connect my laptop to the Internet in Russia. I humbly hope that security experts of this SE could kindly instruct me how I can safely use my laptop in Russia without any risk of getting exposed in relation to my past posts made from Japan from the same laptop, given that at least one Russian who wants to find my real identity may have access to any data related to the use of the Internet in Russia.