An automated procedure is used to make the distinction between “computers” and “devices” (printers, routers, etc). You cannot manually change a machine’s type from device to computer or vice versa.
Lansweeper uses port 135 to determine whether a machine is a computer or a device. If port 135 is open, the machine is deemed a computer. If port 135 is closed, the machine is deemed a device.
What likely happened is that port 135 was temporarily closed on the machine and then reopened. We notice that the machine's computer entry was rescanned after the device entry was last scanned, indicating that port 135 was (re)opened. If you delete the faulty device entries and port 135 remains open, these entries should not return.
In your Lansweeper configuration console under Lansweeper\Scanned Devices, select the faulty entries and hit the "Delete" button. You can filter the "Type" column to more easily find the entries you need.