Wire it to an ACC-controlled line?
Use a relay to turn it on/off with ignition?
Power it w/ the PC's PSU?
Lots of options.
Is it possible to have my tft lcd turned on when i switch on my car too...I mean the problem for me is that the control buttons are momentary switches so i dont see how can i tell the lcd to turn on when i want it to.....cause since its a momentary switch.....how can it be done
If you have a lilliput monitor, you can set it up to auto turn on after power is applied-check the LCD section for more details-- I think it is in a sticky...
then you might need to talk to curious(a member here)http://www.curioustech.net/. i know he has done some small actuation boards like this before for other members(notably, for hijack--who needed a board for a camera display that pressed a button 3 times every time power was applied), but am really not sure what all he offers..