LinkSys WRT54G Stops allowing internet access

My WRT54G will stop allowing internet access every couple of days, more or
less. We had two of these are work which were SEVERAL years older and
they did same thing. I have Vista which I doubt is issue since the older ones
at work had 95/98 and XP machines. Mine is Ver 8.0 with latest firmware
and ones at work were 3 years older and probably never had firmware updates.
My access was only physical so I could power them off and back on.

All 3 stop allowing internet access regularly and had to be powered off to
reset internet. So I think others must be having same problem?
.