Internet Keeps Disconnecting

I have a mid 2010 Macbook. Every time I'm on Safari my internet will randomly stop working for 5 or 10 minutes. Although it says I'm still connected to the internet, safari, or anything else that needs to use the internet won't work, and safari won't let any page load. I tried switching to firefox, but that didn't help. I have a Linksys router. I added a WPA password hoping that would help but it didn't. There are not any problems with the internet on my pc. How can I fix this?