In respect to this, how do I know if a hard drive will fit in my laptop?
Most SATA drives work with 5v and 12v supplies, but a few drives also use a 3.3v power line. The drive thickness may be a restriction. 7 mm drives will fit most laptops. Thicker 9.5 mm (or thicker) may not be suitable for many laptops.
Also Know, can you replace a laptop hard drive with any hard drive? If you have just one drive in your laptop or desktop, you could replace an HDD or small SSD with a one terabyte SSD for less than $150. If you're a computer user with a great deal of data, replacing just the drive that holds your operating system and applications could provide a significant speed boost.
Likewise, can I put my laptop hard drive in another laptop?
Yes, but if he just wants data off of a laptop hard drive, he can place the hard drive in a cheap USB caddy, then plug it into a regular PC or another laptop to get the data off. But the hdd from one laptop will read fine in another laptop. They are just smaller hard drives.
Can I put any hard drive in my computer?
For PCs: Any hard drive will work as long as you know the form factor of the hard drive bays in your case and the connection types on your motherboard. Again, it's most likely 3.5-inch for desktops and 2.5-inch for laptops and most likely SATA connections.