I have written a logon program that looks up the time left in your account (via TCP/IP) and then lets you use the PC for X number of minutes.
When your time is up the logon screen comes up again and blocks you from using the PC. The logon screen is quite secure (no ctrl- alt-del etc), but once you'ce logged in, it's possible to end the timer task.
Because the timer program sends message once a minute, the server knows very quickly, but I'd like to make it more difficult to shutdown the program. I've considered using a device driver - This is how I think it should work:
the device driver is loaded on startup.
when you press a certain key combination, the driver is invoked and brings up the logon box. you log in and when you run out of time, the driver brings up the logon box again.
Does this sound like it can be implemented in this way?
Can you have a hotkey to bring up the logon box? How would this be done?
Would the logon box be part of the driver or a dll?
Would this driver be able to communicate via tcp/ip?
PS. This is probably worth more points, but I'm a bit low right now!