I hope an expert out there can figure out the problem with my Dell
Inspriron 7000 notebook with 15 inch LCD.

This problem has been happening for about a year:
I took it the library yesterday and it worked for about 30 mins or so
then screen went from normal/bright and clear to OFF (actually you can
bearly see the image, not well enough to see the cursor or read the
screeen but faintly... you could make out the image still on screen).

So I closed the thing, it starts to go to sleep mode and opened it
back up and it wakes up... and the screen is bright/worked again for
about 20 more mins then went dark again.

This time the screen would not come back on after closing it. I spoke
to Dell because I had this problem before.  Under warranty I shipped
it to them and they replaced the the "LCD kit" (which includes both
the LCD and wiring harness) and sent it back to me. It worked again
just great for a few months but then started this problem just after
the warranty ran out.

Now it is no longer under 3 yr warranty so they only offer one
solution costing $269 for Dell Depot Repair + $430 for a new LCD (or
Motherboard) = $699 for this P2 worth about $300 even when working
properly... Oh and Dell parts dept. will not sell the LCD for this
model any longer (except via the $699 Dell Depot "deal")

Note the video card drives an external monitor just fine, even when
the LCD is NOT working, so I guess that means the video card is
good???

It has a bag, docking station, NIC card and modem  card etc.  It is a
good notebook with a lot of RAM and DVD and big beautiful screen when
working.  I need the screen to be reliable.  Please let me know if you
can think of a solution.

Thanks,
Mark

I have no experience with such problems, but it sounds like the
backlights are going out.  If you're comfortable disassembling the
laptop's monitor, you can check to be sure, but I'd be surprised if
that weren't the problem.

I agree with haversian-ga's comments; I'm unfamiliar with your
particular laptop model but I had a very similar problem with my old
AST Ascentia machine. In my case, the LCD wiring harness connector on
the motherboard had become very slightly loose - as I remember,
carefully resoldering said connector to the board fixed the problem.
You do need a precise, low power soldering iron, fine solder, and good
soldering skills though - if you were not confident of your abilities
in this area, I'd leave the work to someone with such ability,
otherwise you may easily overheat & damage adjacent motherboard
components.

I have been researching this very same problem for a friend with the
same machine. The problem lies with the "Inverter" gone bad. This part
is responible for lighting up the LCD, located just under the screen.
I have not been able to locate this part yet for sure. Check this page
out "http://www.notebookparts.com/products/description.php?II=761"

This is another site:
"http://www.timports.com/products/electronics/computer/notebook/parts/compal/30i2/"
It is called by another name but the same inverter as your. You can
also find this part at ebay for $24.95.