Please capitalize where necessary: thank you. i am now signing up on all social bookmarking platforms that you’ve suggested in your post.
A: Thank you. I am now signing up on all social bookmarking platforms that you’ve suggested in your post.
Q: before you can open a fakrack2 file, you'll need to figure out what kind of file the fakrack2 file extension refers to.

A: Before you can open a FAKRACK2 file, you'll need to figure out what kind of file the FAKRACK2 file extension refers to.
Q: it is a grace that enlightens the passage into the new millennium and helps us to grasp the beauty and trus depth of our vocation imprinted in the charisma and spirituality passed on by father dehon.
A: It is a grace that enlightens the passage into the new millennium and helps us to grasp the beauty and trus depth of our vocation imprinted in the charisma and spirituality passed on by Father Dehon.
Problem: what impression do you have in general the opinion of the population of united kingdom? especially young people who in the end and after who live more years conditioned the decision expressed today at the polls if such measures are applied, largely supported by the people of advanced age.
Can you repeat this sentence, but capitalize it?
Answer: What impression do you have in general the opinion of the population of United Kingdom? Especially young people who in the end and after who live more years conditioned the decision expressed today at the polls if such measures are applied, largely supported by the people of advanced age.
Text: confidence. enthusiasm. strong emotions.

Correct capitalization: Confidence. Enthusiasm. Strong emotions.
Text: new digital screens in copenhagen airport can detect the attention, gender and age of people passing by and in the long term be able to shift between ads in relation to each individual.

Correct capitalization:
New digital screens in Copenhagen Airport can detect the attention, gender and age of people passing by and in the long term be able to shift between ads in relation to each individual.