When i start up my computer, the USB mouse (Dell/Logitech wheel mouse) doesn't work.
If i simply unplug it rom the usb hub and plug it back in, it works perfectly.
What is going on?

What distribution? What kernel? Do you have other USB devices? Is the proper USB modules set correctly in /etc/modules.conf (or /etc/modprobe.conf)?

You mentioned that you are using a hub. If you connect it directly into one of the usb ports, does the problem persist?

It works fine if plugged directly to the computer, no unplug/replug necessary.

At one time, I did have the mouse plugged into the USB hub andworking normally.
I previously had a serial mouse. Then i got the USB mouse.
Originally, i just plugged the USB mouse into the hub, while still leaving the serial mouse plugged in because xwin would lock up without the serial mouse.
At some point, i finally got kudzu to remove the serial mouse and install the USB mouse, but after that this problem showed up.

RH9, kernel 2.4.20-8

/etc/modules.conf------------------------------
alias parport_lowlevel parport_pc
alias eth0 sis900
alias usb-controller usb-ohci
alias usb-controller1 ehci-hcd
alias usb-controller2 usb-uhci
alias char-major-195 nvidia
alias eth1 8139too
alias sound-slot-0 i810_audio
post-install sound-slot-0 /bin/aumix-minimal -f /etc/.aumixrc -L >/dev/null 2>&1 || :
pre-remove sound-slot-0 /bin/aumix-minimal -f /etc/.aumixrc -S >/dev/null 2>&1 || :