can a immigrant who was born in pakistan but later moved to russia become russian president?

he can if:
- he gets Russian citizenship
- he is older than 35 y.o.
- permanently lives in Russia for no less than 10 years.

Check here (it is in English):
http://www.constitution.ru/en/10003000-05.htm

only if his parents were Russian

In any corrupt society anything can be bought

anyone can be a Russian president if they kill and payoff the right people...

No. Only Russian citizens.