I have a 5 year old Dell now with a P4 @ 1.8ghz. No upgrades, no OCing, no cleaning, no special care of any sort. Just sits under my desk in a not-so-well ventilated area. I leave the computer on 24 hours a day, 365 days a year. I don't even put it into hibernation. Just turn off the monitor every night and go to bed. It's survived in these conditions ever since I got it. I'm about to upgrade to a new, high-end system and want to know how it would fare in the same conditions? The only significant change I see would be that it would be in a better ventilated area with a better cooling system and it will recieve regular cleaning. Can the high-end systems of today be left on indefinately? I wouldn't mind putting it into hibernation every night if I had to, but what do you think? Anyone out there who does this? Leaves their computer on ALL of the time?