You haven't applied recent upgrades. The most recent 2.0.x kernel
is 2.0.38, released last month. 2.0.35 was released more than a year
ago (and more recent releases actually do fix some relatively minor
security issues --- e.g., an extremely obscure TCP spoofing attack).
Applying kernel upgrades forces you to reboot at least as often as
they appear, and should therefore be helpful in reducing your mean
time between reboots substantially. Regrettably, though, userland
upgrades under Linux do *not* require reboots, so you still probably
won't achieve the brisk rate of reboot activity commonly associated
with software of true commercial quality such as Windows or Win NT
(which sometimes even help you out by rebooting entirely on their
own!)
rst