From Brussels Airport (Zaventem) to Microsoft Centre Brussels

By train: 

At the airport go to level -1 and take a train to Brussels. Leave the train at Bruxelles Midi station, then take the metro line 2 or 6 until "Trone" (directions Elisabeth) and walk 350 m via Rue Montoyer.

By bus:

Take bus number 12 or 21 which leaves from level 0 at the airport and get off at Luxembourg. The bus ticket costs and the journey takes about 30 min. For the bus go to the following link: http://www.stib-mivb.be/index.htm?l=en select “Timetables and realtime” and then select B 12 or 21.

After you got off at Place du Luxembourg walk 550 m via Rue de Treves and Rue de Montoyer.

From Charleroi Airport to Microsoft Centre Brussels

By bus:

Take the Brussels City Shuttle bus which takes you to the Brussels Gare du Midi (main train station). A return ticket costs 22 euros (and one-way ticket 13 euros). For the bus schedule, see here:

http://www.charleroi-airport.com/en/brussels-south-charleroi-airport/index.html

From Bruxelles-Midi / Brussel- Zuid train station to Microsoft Centre Brussels

By metro: 

Take the metro line 2 or 6 until "Trone" (directions Elisabeth) and walk 350 m via Rue Montoyer.