Replacing a hard drive in a laptop looks easy, but one has to consider that many laptops are designed with a specific hdd in mind, and simply replacing a small capacity one for one with higher capacity isn't always a good idea. The larger capacity drive is more than likely to run significantly hotter and may require a level of cooling that isn't provided within the current case.

So great care should be taken when changing laptop hard drives, and the person doing the changes should soak test it doing something challenging in both CPU and hard drive accessing before handing it back to the end user.

Plus, no matter how much money you spend, don't put a laptop on your lap. Expensive Sony's started going phut and catching fire, with overheating faulty batteries not too many years ago. Some of these were 2 or 3 years old! The moral being - you never know.

A better description would be portable personal computer or notebook computer.

Actually, that's not likely to be true these days. The Seagate Momentus 7200.4 series has the same power consumption and heat dissipation from 160GB to 500GB. In general, it takes the same or slightly less power than the slower 5400.6 series, and both take around two-thirds of the old Toshiba 80GB 5400 stuff.

I updated my ThinkPad to a bigger hard drive (and Windows 7), and it runs faster and the drive is cooler than before.

Look at the power consumption ratings on the drive specs. Same power = no problem.

The tricky bit comes with different interfaces - care is needed there, now, to get a drive that will fit and work.