Phil, reading the problem pages in ComputerActive magazine, they always recommend that you take the problem back to the vendor first. Because your laptop is in warranty, they should do a straight replacement. Or is it from Dell?
I had the same problem Sunday night! Luckily the ‘Boot in Safe Mode, Shutdown and Boot again’ method worked for me!! Did AVG scan, Adaware, Spybot and CrapCleaner then ScanDisk and Defrag. All seems OK now. By the way, Adaware found 37 critical objects!!