I have found this problem caused y sp2.. sometimes even after a while of using the machine with sp2...
Trie running it throuch the recovery console and doing a chkdsk... that may just fix it....
Good news, it should not mean a dead laptop..
http://www.hardwareanalysis.com/content/topic/31874/
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oh and for cleaning a tft screen, soft damp cloth and a good wipe dry normaly does the biz