My internet is spasming o.O

[t3h l337 n3wb]

I have 2 computers hooked up to this network. One is wired, and this one is wireless. The wired one is usually turned off. I have a Linksys 54G router/4 port switch. Sometimes, when I load a page in Firefox, it will like stop loading it and freeze up, so I'll have to hit refresh a couple of times. Also, whenever I try to download an update for Zonealarm, the download freezes halfway through. This is getting pretty annoying... Any ideas why I keep getting random pauses?