My Dell Inspiron 9100 pc replacement (it's too big to be considered a laptop) was bought in 2004 and has been on for 15 hours a day virtually ever since. I run it off the mains as the battery died years ago. It is sluggish but a more knowledgeable friend says a Windows re-install should sort that, I just can't be bothered to take the time to do it. All my files are backed up to an external hard drive so I suppose I'm just waiting for it to die before it gets replaced.