You mean reboot?
1) Go to Start > Run.
2) Type "telnet" without quotes.
3) In the telnet window that opens, type "o 192.168.1.1" (o for open, replace 192.168.1.1 with your default gateway address) without quotes.
4) You will get a login prompt. Enter your username and password (The ISP one, not the router one) At # prompt, type "reboot" and press enter.
For scheduling the reboot, download TST10 from winsite.com downloads. It is a tiny freeware Telnet utility with support for scripting. Extract the utility to a folder on your hard drive. e.g. C:\TST. In this folder, create a new text file. This is the file in which we will write the script for TST10, so name it anything you like e.g. reboot.txt. Edit this file in notepad and type the following. Remember to type the quotes as well and do not type the top and bottom lines, which I've added here only for clarity.
Start of script(don't type this line)----------------
192.168.1.1 23
WAIT "login"
SEND "login_id\m" (enter your login ID here)
WAIT "Password"
SEND "login_pass\m" (enter your password here)
WAIT "#"
SEND "reboot\m"
WAIT "#"
End of Script (don't type this line)-------------
192.168.1.1 is the address you use to access the router configuration. 23 is the port to which telnet connects. Replace "login_id" and "login_pass" with the login and password respectively, that you use to access the router configuration page from a browser. Remember, keep the \m after the id and pass.
Now simply create a scheduled task using the inbuilt Windows task scheduler.
Important: Create a task to run tst10.exe with the command line parameter /r:reboot.txt.
Important: Remember to set your firewall to always allow TST10.exe to connect to 192.168.1.1 otherwise it won't be able to work.