I can economically recover data in most circumstances without resorting to specialist services with clean room facilities (its very expensive if you need it).
Usually most or all data can be recovered in the following circumstances:
Old laptop or desktop computer you have retired
Desktops or laptops when you can no longer login
Dead laptop or desktop computer that won’t turn on or comes on but promptly switches off again
Desktops that fail part way through the boot process
Virus infested computers
Very slow computers due to failing disk drive (usually shows as intermittent complete pauses of 30+ seconds often followed by a period of normal behaiour and then more pausing)
Often all or most can be recovered when:
No boot device message at start up (if you have disk or usb memory plugged in simply removing and restarting may fix this problem)
You have deleted the data - as long as you stop using the computer
Some data can usually be recovered (the amount will vary greatly):
You have formatted the disk or recovered to initial setup
Disk drives failing to start or be recognised are either a complete no go and would need a clean room, but it is still worth checking as their failure to start is quite often not a disk problem. The problem with the disk is just a manifestation of another problem in your system.
If you bring these to me I am happy to make an initial assessment for free.
Computer and Memory Card Data Recovery by Repair a PC