Compaq Presario V2000 will not boot.

Is the Targus ac70u the factory power supply and was it the same one you used to successfully boot previously? If it isn't and is a third party power supply, you may have one or two issues. Either it is not supplying enough power for the laptop or too much and/or the polarity on the tip could be reversed. The factory one is 65W I believe so make sure you are getting the right amount of wattage. If the aftermarket power supply has a voltage selector, make sure your setting is per the specs on the bottom of the laptop or the setting just above (i.e. if the laptop calls for 13.6 volts and your supply switches from 13 volts to 14 volts, leave it on 14 volts as the lower setting won't work right). Lastly, if it has a detachable two-prong tip, you might have the tip backwards which reverses the polarity of the positive and ground terminals in the tip so try switching that. Hope this helps! Is the Targus ac70u the factory power supply and was it the same one you used to successfully boot previously? If it isn't and is a third party power supply, you may have one or two issues. Either it is not supplying enough power for the laptop or too much and/or the polarity on the tip could be reversed. The factory one is 65W I believe so make sure you are getting the right amount of wattage. If the aftermarket power supply has a voltage selector, make sure your setting is per the specs on the bottom of the laptop or the setting just above (i.e. if the laptop calls for 13.6 volts and your supply switches from 13 volts to 14 volts, leave it on 14 volts as the lower setting won't work right). Lastly, if it has a detachable two-prong tip, you might have the tip backwards which reverses the polarity of the positive and ground terminals in the tip so try switching that. Hope this helps!