My HP Envy x360 has been having an intermittent boot problem for nearly a year. Occasionally, it starts to a blue recovery screen saying that no operating system is installed, even though I was using Windows normally just a few minutes earlier. The built-in diagnostics report no problems, but the suggested recovery process requires downloading Windows, which is impossible when the laptop will not boot. Strangely, tapping the side of the laptop firmly against the floor sometimes makes it work again, anywhere from an hour to a month. I believe the storage is an SSD. Could it be loose, failing, or related to the CMOS battery or motherboard? I would prefer to repair it rather than replace the laptop.
4 Answers
The SSD is the most likely suspect, especially since physically tapping the laptop temporarily restores booting. It could be a loose connection, a failing drive, or a damaged solder point. Back up your important files immediately while it still works, then have the SSD reseated or replaced. Reinstalling Windows will not fix a bad connection or failing drive.
A weak CMOS battery can cause BIOS settings or the system clock to reset, but it is less likely to explain a problem that improves when the case is tapped. It is still worth replacing on an older machine, but I would prioritize backing up your data and testing the SSD and its connection first.
Since the issue involves opening the chassis and possibly replacing an internal battery or SSD, a repair shop may be the safest option if you are not used to working inside laptops. Ask them to check whether the storage drive is detected reliably, inspect the connector and motherboard, and test the SSD before attempting a Windows reinstall.
If you are comfortable opening the laptop, remove and reinstall the SSD and make sure its retaining screw and connector are secure. Also check whether the BIOS consistently detects the drive. If the drive disappears from the BIOS, the problem is probably the SSD or its connection rather than Windows itself. Avoid hitting the laptop, since that can damage the drive or motherboard further.

I had it inspected once before and was told nothing looked out of place, but I will make sure the drive is tested specifically and back up my files before opening it again.