I just started to play left 4 dead 2 on my dell laptop. I would say if you have good configuration like 4GB RAM, 2GB graphic card and i7 processor then you can enjoy this game in good speed.
If you are beginer then I would suggest play offline and single with easy mode and select street. Inhostel and mall you will feel uncomfortable.
Anyway game is really good I have just completed two levels in street till diliver coke to door only.