This is probably a motherboard issue
Your symptoms strongly suggest an electronic problem in the motherboard, since you've noted that it always happens before Windows starts booting up. It's quite unlikely that a laptop AC adapter would do this as the battery should be able to keep the system running even if the adapter failed. If you can confirm that the battery charges, your AC adapter is most likely good. Note that the CPU and GPU are soldered onto the motherboard on this laptop.
A hard drive failure wouldn't cause these kinds of boot-up issues as the system should be able to get through POST, just not load the OS. Bad or improperly-seated memory wouldn't explain this problem, either, as this would manifest as frequent random system and application crashes or the system giving a beep code when powered on, respectively. It's incredibly unlikely that these parts would cause the system to not clear POST with nary a beep code.
The motherboard is almost never a user-serviceable part in any laptop, so you should send it back to Dell for repair. Be sure to back up your data—the best way to do this is to remove the hard drive from the computer, put it in an enclosure, and plug it into another computer for data transfer or imaging.
The inspirion shouldn't be that old. Have you checked the warranty status? (www.dell.com/servicetag) Probbly you bought a bundle with extended warranty. – marsh-wiggle – 2014-12-10T07:51:49.203
yeah thats last option, but if there is any option to diagnose – codeomnitrix – 2014-12-10T16:12:15.133
When it does boot, can you check your logs? – Andrew – 2014-12-16T13:12:34.517
I suggest using a bootable USB flash drive. That way, you can rule out hard drive failure. – Behdad – 2014-12-16T14:13:40.757
When laptops have sudden shutdown errors, it is good to check if they are overheating. Have you tried air dusting the exhaust port? Have you tried not using it in bed with a blanket/comforter? Have you tried putting a paperback novel in the back of it to get it to tilt, increasing airflow? – AdmiralThrawn – 2014-12-16T14:15:58.543
Also, run a hardware diagnostics CD, if you have one available. Unfortunately the ones that test all of your hardware components and not just something specific like the RAM are usually proprietary. If they developed a good one that was freeware/shareware, computer diagnostics and repair would become much more accessible to the layman. – AdmiralThrawn – 2014-12-16T14:17:25.350
Hi, I have checked the warranty status, its out of warranty. Can you pls suggest something. Last option I think now is replacing motherboard. Thanks – codeomnitrix – 2014-12-20T08:09:12.893
Try to remove the RAM and place it in other socket. If you have two ram then swap it in each other. or you can try to remove one RAM at a time and then try. Hope this help. – Calculating Machine – 2014-12-23T05:33:08.070