Repeated repair/resolution failures, Laptop (US)

My wife's Inspiron 3542 laptop (still under parts and service warranty, purchased last summer) started experiencing failures in mid-December.  The laptop would not power on, and was completely un-usable.

Since that time, I have spent many hours' worth of tech support sessions, and we have shipped the laptop to Dell for repair TWICE.  The first time it was "fixed", they only replaced the AC adapter (received mid-January).  We just received the laptop back yesterday from the second attempt, and it will not power on at all.  During the last troubleshooting session, the tech support person determined that it was apparently a motherboard issue, and must be shipped in.  On the repair paperwork, it says that they replaced the hard drive and operating system.  The hard drive had already been replaced!

We are coming up on almost 2 months of having an inoperable laptop that is nearly brand new, and I'm told that they will not send me a new one because my warranty only covers parts.  That is fine, but thus far I have not received satisfactory service. 

I *plead* with Dell...please send me a working laptop for my wife to use for her school.  The one in my possession is completely inoperable and has had repair attempts made twice, a new hard drive shipped to me, support CDs mailed to me, and other support sessions made to try to troubleshoot my issues.  I don't understand why they cannot fix it properly.  Please email me and I would be happy to set up a phone call or provided other information.