Laptop shuts down automatically in few seconds

Today, one of my friends came up to me and said that his laptop was having some problem. He said that when he pushed the power button, it blinked for several seconds, but no video was displayed. In the evening I went there and saw the same problem. The good news is that I fixed the problem eventually. To know how I fixed the problem, please read below:

First of all, I tried simple things because I didn’t want to make the thing complex. I removed the battery and started the laptop with an AC adaptor. I removed the hard drive, the DVD drive and wireless card, but nothing helped. I went a little bit further – I opened the laptop case, removed the LCD screen assembly and reseated the video card. Eureka, eureka… the laptop started working. I assembled everything back in position. I am really happy that I fixed up my friend’s laptop.