A little spinning circle with a black background and the boot logo appears to be fixed in position. Regardless of whether Windows is using an older or newer version, this issue is fairly typical.
For Windows 10 and 11, try one of the following fixes if you can’t proceed past the login screen.
Use a Safe Mode’s powerful troubleshooting options.
It’s likely that you won’t be able to access your login screen when your machine is in an endless boot cycle. Here’s how to get access again.

Step 1: Before removing the battery, unplug the power.

Step 2: Long-press the Power button for at least 30 seconds. Any remaining charge in the circuit will be eliminated as a result.
3. Connect the power source once more and reinsert the battery.
Step 4: Use the Power button to restart the computer, but press the Start keys to start it in Safe Mode. The keys differ depending on the PC maker.

Next, pick from one of the available choices:
Remove latest Windows updates, perform System recovery,
PC reset

Get rid of any unwanted third-party programs at starting

You can delete any unwanted programs that are currently executing during startup to prevent further disruptions. The next time Windows starts up, some installed third-party application tools often launch. They are the ones who need to go.

Step 1: Press the Win + R keyboard shortcuts to bring up the Run command menu.

Step 2: To open the Registry Editor, type regedit.

Step 3: Open Registry Editor and then take the following steps:

Computer/HKEY_LOCAL_MACHINE/SYSTEM/CurrentControlSet/Control/ServiceGroupOrder

Step 4: To open a new pop-up window, double-click the List menu item.

Step 5: You can view a complete list of Windows processes and external apps that are active in Windows startup in the Edit Multi-String window. Consider deleting any unwanted programs, such as antivirus software or other apps from a third party.

Step 6: You should also get rid of as many startup programs as you can. From the search menu, enter “Startup apps.”

Remove bloatware
Numerous cumbersome applications have the potential to significantly slow down the Windows launch procedure. It might be safer to entirely remove them from your Windows computer.

A completely new installation of Windows
One solution suggested by Microsoft to solve the delayed starting issue is to perform a clean install of Windows.

Master Boot Record repair

The master boot record (MBR), which guides your computer how to load its operating system, is the first sector that must be read when your computer accesses your hard drive after booting. Your computer cannot find the instructions it needs to boot when the MBR is damaged, and it becomes stuck in a loop.

1. Choose Troubleshoot > Advanced Options > Command Prompt when your computer enters WinRE.

2. Run the following three commands when the cmd window appears:

• bootrec /RebuildBcd
• bootrec /fixMbr
• bootrec /fixboot

3. Next, use the command below to fix the boot sector.

bootsect /nt60 sys

4. In order for the changed settings to take effect, restart your computer. Check to see if the Windows 10 or 11 boot loop/unbootable to OS problem has been fixed at this point.