I cant connect my computer to my tv tv is showing no signal

[sri3]

Hello,
i am using window's XP system i am unable to connect my computer to VIZIO tv,can you guide me how can i connect.
do i need any devices are download.
I donot have any idea in this.
please help me.

thank you

 

[Emerald]

Desktop or Laptop?

how did you connect the TV? via VGA cable?