if it is a .deb then you are running debian based distro, it is even easier...
deb-pkg -i NV (hit the tab) and off you go.
again in order to install drivers you will need to be root, so no need to muck around with chmod and chmod 777 is a bad idea for drivers. this gives everyone read/write/execue permissions to the file even guest accounts have full access to that file. bad idea.
the easy way to install the nvidia drivers on your debian box will be as follows:
grab the drivers for your flavor 32bit or 64bit
this is the direct link to the 32bit vs:
read this link:
that is the detailed HOWTO guide for the nvidia drivers... very easy to follow.
apt-get install sysv-rc-conf ksysv
both of those tools are easy ways to configure your startup. in runlevel 3 remove everything that has to do with the GUI, also you can do this for runlevel 4. only runlevel 5 should have anything to do with the GUI. do not touch runlevel 1 or 2.
then set the default runlevel to 3. reboot the system.
read that link for more details on debian runlevels.
after you have those steps done, should not take but a few mn. longer to download the drivers then to do the runlevel steps. you can log into the CLI as root and navigate to the directory you downloaded the nvidia drivers from above.
type in sh NV (then hit the tab) and you will be set. follow the directions and make sure you have the proper headers installed for your kernel.
debian uses some odd name schemes from time to time to get things done but still a fast apt-cache search linux | grep 2.6.x.* to match your kernel vs will not take long.
with the .deb file you have you can also just do as i stated above and as ROOT from the CLI just type dpkg -i NV (hit the tab) and away you go.
sorry i goofed on the command earlier. been about 6 months since i did any debian work.