Dell 14" 5447 dead

Hi,

I have purchaced Dell 14" 5447 in Jan 2015. Within 2-3 months there was some issue with headphone jack. I complained it to dell and they sent a technician. He didnt rectified the problem and replaced my new motherbord with a refurbished one. I was unhappy about it as it was new laptop and under warranty and I expect it to be replaced with a new one.

Again after 6 months i.e. Oct 2015 suddenly my laptop was dead(sometimes it starts up). I again called Dell support, they sent a technician and again he replaced the motherboard and it worked fine.

Now, yesterday suddenly my laptop is dead(but starts once in hundred attempt). Since its not under any warranty Dell support is forwarding my calls to off warranty support. I am very dissapointed with the service as I was given faulty motherboard repeatedly.  Can I get a replacement of my motherboard?

Could it be a faulty CMOS battery which is causing the issue since it starts sometime? Any help?

Regards,

Sridhar