Inspiron M5010 - 7 beeps at start up(not powering up) -- why dell laptops life time is less than 3 years...?

I bought my laptop 2.5 years back. my primary reason for buying dell laptop is expecting good customer service. Till 2 years i didn't get any problem. After that it started troubling me with 7 beeps sound and sudden memory dump problems. If i go for dell support they are asking around 18k. Irrespective of my friends suggestions i bought this laptop by expecting good support.But it disappointed me lot.By this experience i got a great lesson not to buy any dell laptop. still i don't know why dell is not able to produce quality laptops.