I am still confused. So Initially the company knew something was there on LV 426. They knew because its beacon repeated every 12 seconds. The Company heard and deciphered the beacon some time prior to the Nostromo's trek to retrieve ore from Thedus. Two weeks before the Nostromo set "sail", the Company replaced the old science officer with Ash, whom they have preprogrammed to enact their plan of retrieving and protecting the alien life form. They then re-routed the Nostromo to the same area. They knew that the Nostromo would pick up the distress signal and, according to Company regulations, would be forced to respond to it, and Ash would be there to make sure that the mission was carried out.
Is this right so far?
Then accessing the ship's computer, Ripley discovers that Ash has been ordered to return the Alien to the Nostromo's corporate employers even at the expense of the crew. So now the Company knows about the Alien and how dangerous it is right?
Then we all know what happens next. Yada, yada, yada, Ripley escapes threw shuttle and goes into hyper sleep.
Now in Aliens some 57 years later the escape shuttle was picked up by a deep salvage team hoping to claim possession of the "wreckage." They discovered that Ripley was still alive. Ripley has an interview before a panel of executives from her employer, the Weyland-Yutani Corporation. She gives them the coordinates to the Derelict. So the distress signal obviously stopped some time ago. Then Ripley finds out there is a colony on LV 426, and the colony never came into contact with any hostile organisms.
So the company never knew the exact location of the Derelict, they only knew it was on or near LV 426. The Company probably listed the Nostromo as 'missing', but they may have sent an investigative crew to the planet, landed on the opposite side from where the derelict ship landed, and found nothing. Another possibility is that the Company may have wanted to cover up the entire incident. An elaborate investigation into the disappearance of the Nostromo might have revealed that they sacrificed the crew in order to obtain a specimen of the Alien. In order to protect the Company, they may have buried the incident until there was an opportunity to have the colonists on LV-426 take a look. It's possible that the Company may actually have sent the colonists to LV-426 for just that purpose. Later on Ripley finds out that Burke was the one who deliberately sent the colonists to investigate the derelict ship after hearing about it from Ripley's testimony.
So Burk acted alone by sending the colonist the coordinates to the derelict, but it is possible that the company was also still interested in the in it because they put the colony on LV 426.
Is this right so far? If so then I hope it answers some of questions and confusion going around here.