The power light keeps flashing

It means to say that it is not getting enough power on the computer, check the power cable at the back of the tower and make sure the power cable is connected tightly. You can try taking it out and then putting it back in again to make sure it is connected firmly.

hi,
if only leds are blinking then please check the following
1.the dell logo or any other thing is coming on monitor and if not then disconnect the vga cable and check any message is there on monitor if any message like power saving mode or no input signal is there monitor is ok.
2.check with the tapping of num lock if it is responding then disconnect all the cables and then press the power button for one minute and check after reconnecting all the cables.
3.if num lock is not responding might be the issue is with motherboard.