750 GB Hard Drive Failures in XPS 420

My OEM 750 GB drive failed in my 5 month old XPS 420 about 10 weeks ago, and the replacement Seagate Drive failed yesterday (Monday Jan 19th).  It's going to be replaced by a local Dell subcontractor tomorrow, but my fear is something is causing these failures which will result in a third, troublesome failure down the road.  Whether it's a mother board issue or not I can't tell, but I have no unusual software, I do regular maintenance, generally do full Shut Downs, and I'm not a gamer. If I didn't have most things backed up, it would be a disaster.

I think these failures cost Dell time and money, as well as considerable inconvenience for a longtime Dell customer like myself.  I think it would not only be in my interest, but in Dell's interest as well to take this XPS 420 back and do an appropriate rebuild and ship me a new one. I saw a similar complaint from an XPS owner for 2 hard drive failures on her XPS on another forum.

The XPS technical support staff has been as helpful as possible on the phone, but there's something going on here which they can't solve (and, obviously when the SATA 0 drive can't be read, they cannot Webex).  Until now, I've been a very satisfied Dell customer, and I work with Dells in my workplace as a meteorologist as well.  I admit I'm surprised at this lack of reliability in what is clearly a great computer--when it's working.

Thanks for any response,

Don Paul