About two or three years ago I think a probe whose name I forgot has been crashed into an asteroid at high speed to see what would happen if we tried to collide something with an asteroid on Earth course. The asteroid the probe was crashed into had a moon as well. What were the results of the crash? Did the asteroid slow down? Did it change direction? What happened to its satellite?
If you're thinking of the NASA DART mission (Double Asteroid Redirection Test), it hasn't launched yet. It's supposed to depart Earth between November 2021 and February 2022, and encounter 65803 Didymos and impact its satellite Dimorphos in September or October 2022.
DART is the first part of the AIDA collaboration (Asteroid Impact and Deflection Assessment). The second is the ESA Hera mission, planned to launch in 2024 and survey the Didymos system in 2026. Better answers to your questions will be available after that.
This is to add an update now that the impact has taken place.
I also think the spacecraft you are talking about is the DART Mission (the Double Asteroid Redirection Test.)
The impact took place on 26 September 2022, at 23:14 UTC.
As to the question itself:
About two or three years ago I think a probe whose name I forgot has been crashed into an asteroid at high speed to see what would happen if we tried to collide something with an asteroid on Earth course.
It is possible that you read the news of the projects progress rather than the actual impact:
In June 2017, NASA approved a move from concept development to the preliminary design phase, and in August 2018 the start of the final design and assembly phase of the mission. On 11 April 2019, NASA announced that a SpaceX Falcon 9 would be used to launch DART.
The asteroid's name is Didymos and it's satellite, Dimorphos was the target of the impact. It's motion didn't change much, however, NASA was happy because the asteroid's orbit did change and was shortened by around 10 minutes.