silly question but, I bought a laptop for my eldest for xmas to replace her aging desktop. She is in the habit of leaving it switched on and running for upto 48hrs at a time, is this ok? or does shes run the risk of "burning it out"?
When you close the lid, laptops by default go into stand-by mode whereby they virtually shut down and use very little power and produce very little heat. You can leave them like this almost indefinitely without harm.
As spikeychris said, just make sure that air can circulate around the laptop - leave it on a firm surface.
As spikeychris said ther is no problem with leaving the laptop on for extended periods. I do it for weeks at a time. Ventilation is essential though and I often use a marker pen or book to raise the laptop up to increase the air flow as the intake is from below. No probs so far over 5 years 24/7