Windows explorer closes intermittently

[Gary]

I have a Dell Dimension 8200 desktop hooked to a cable
modem thru a Linksys wireless router. The wireless
router provides Internet Connection Sharing to a Toshiba
A35 series notebook.
Intermittently on both computers, when the windows
explorer is open, the explorer will close, and all
desktop icons disappear for approximately 3 seconds. Then
all of my desktop icons reappear. But the explorer
remains closed.
Both machines are running XP Professional with all
current updates.
What causes this?

 

[CWatters]

Does this happen everywhere or just when you explore one folder?