Inspiron 6400--Lemon?

I've had it for a year, and it crashed a week out of the box. Tech support had me reformat it, and it's always been really slow.
Before a year was out the optical drive died (they had to send a replacement I installed myself).
I've never been able to move it from my desk because it crashes each time and then refuses to read hardware components.
It consistently gets hot after 1/2 hr of use, and tech support told me that it won't harm the computer, but I'm not sure about that.
It crashes repeatedly (not just lately but for the entire year I've had it) regardless of what I'm doing (or even when I'm not doing anything). It particularly doesn't like Microsoft Office. Tech support walks me through fixes, but in all my calls they've never actually fixed it and they actually end up apologizing for not knowing what's wrong.
The sound has serious hiccups (again, they've never been able to figure out how to fix it--it's not the hardware).
It crashed again last night and they walked me through another reformat, but now it won't even boot/turn on from the reformat because it's so corrupt ("volume is dirty"). I only use it for email, basic internet and Microsoft Office; there's almost nothing on it. Their Gold Service tech guys can't figure out what's wrong with it and want to have me replace all the hardware (hard drive, memory, and if that fails, the motherboard) piecemeal to see if MAYBE that will fix it. Over the course of a year, I've spent dozens upon dozens of hours on the phone w/their tech guys, who still don't know what's wrong. Now they want me to take even more time trying to start from scratch, replacing parts and reformatting again. The computer has been plagued with serious problems from the day I bought it a year ago.

I can't be without a reliable computer--I need it for work.

Is there such a thing as a lemon computer? How should I handle this with Dell? I can't afford to spend even more time trying to fix it again, let alone time w/out a computer. Am I wrong to insist on an equivalent system replacement?

 

You should probably hand it off to Dell as a lemon; unfortunately, laptops have become far less reliable than they used to be. They used to offer 3-year warranties with all their computers, however as laptops have become mainstream products (more and more people can afford them as they become cheaper) and outsourced manufacturing to other countries, quality has gone down. As a result, laptops are not only unreliable because of their design, but also because of their manufacturing quality and standards.