I think the right course of action is definitely to call Dell support, tell them your screen has turned in to a Rothko, and see what they do. I'll be so happy if they can diagnose your problem on that information alone.
As for a new computer, if you happen to get a winning scratchie some time soon, there's the new MacBook Air, which fits inside a manila envelope, and is incredibly small and sexy. Comes, of course, with OS X, but is intel-based and comes with Boot Camp, which is a very easy-to-use dual-boot system, so very Linux-friendly. About $2300 with ed discount.
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As for a new computer, if you happen to get a winning scratchie some time soon, there's the new MacBook Air, which fits inside a manila envelope, and is incredibly small and sexy. Comes, of course, with OS X, but is intel-based and comes with Boot Camp, which is a very easy-to-use dual-boot system, so very Linux-friendly. About $2300 with ed discount.