how can u uninstall a driver

Hai everybody…
how can u uninstall a driver completely? even though i am removing the PCI device from Device manager, deleting the inf and driver files from my system directory and try to install my current driver. but operating system is not recoganizing the changes whatever i have done in my current driver .but once if i restart, it is working. is it always necessary to restart? please help me.
Thanks in advance.

regards,
bala.R

Sounds like the driver is not unloading. There is probably still a
device handle open or some other reference to the driver. I would put
a debug message into the unload routine so that you have a positive
way to verify the driver being unloaded. I find that very useful in
development when I want update a driver and be sure that the update
has been loaded.

Robert Newton