how to reject inconsiderate request?

I need some opinion on the following situation I’m faced with:
I’ve been approached a few times to troubleshoot a pc problem for one of the managers from my company. He isn’t my manager but I’ve helped him on a few occasions. The problems is that he lives in my neighborhood and he had approached my house a few times before, on weekend eveinings, to help him with some pc issue! (he did it once during my maternity leave!) I didn’t want to be rude to him but I don’t feel I’m obligated to such thing after work and it wasn’t even a work computer. What should I do without hurting his feeling?