One thing I noticed (I think...maybe I'm just being superstitious), is that you have to start 'clean' when you use one of these coupons...remove everything from all of your carts, then close ALL BROWSER WINDOWS so that you are completely logged out of the Dell site...next, open a window and go to Dell's main site and pretend like it's the first time you've been there...DO NOT log in...just load up a laptop in your cart, apply the coupon, and THEN tell them who you are...also, try not to let the automated system 'give' you any rebates or accessories during your trip through configuration...no rebates, no free printers, no anything...just load up the laptop, try to remain anonymous, and don't take any other 'deals' like mail-in or instant-off rebates, etc...
Again, the above may be total BS and nothing but superstition, but this is how it worked for me last nite...the first time I tried logging directly into my cart and applying the coupon, it was giving me all kinds of crap about how the coupon expired or I wasn't eligible & etc., but then I just pretended to be some newbie and it worked with the new coupon-- CXFLV5J8Q4?LBV
Good luck...I saved like $1250 and got an XPS2 w/2.13Ghz Proc for under $2000...almost unbelievable considering I bought my first one for $3200 five months ago...