The short answer is...
Open a command window and run "ipconfig /all".
If "DHCP Enabled" is YES, write down the default gateway address and DNS addresses.
Now "ping 192.168.0.2" and make sure it's not in use.
Open the properties dialog for the LAN entry in question.
Select "Internet Protocol" and open its properties dialog.
If "Obtain an IP address automatically" is selected ("DHCP Enabled" would have been yes), the entry fields will be grayed out, so select "Use the following IP address".
Enter the ip address you want, let the subnet mask default, and use the default gateway address you wrote earlier.
Enter the DNS addresses in the lower fields.
Save everything.
No need to reboot.
That was the "short" answer.
The long answer depends on...
What's the exact model of router
How many other computers are on your LAN?
How did you get the address you're using now?
Is the router functioning as a DHCP server?
Could the router hand out the .2 address to another computer?
Can you configure your router to NOT hand out the .2 address?
etc, etc.