I removed the "boinc_admins group"
"boinc_user group"
and all other accounts start with "BOINC" on windows 10. while I did not uninstall BOINC．

Then I finally realized I made a big mistake, and while I trying to run the BOINC, it doesn't work. It can't be uninstalled, and can't be reinstalled.

I would use regedit to see what entries for BOINC there are. The usual warning applies,

Before changing anything using regedit back up the registry first!

Check to see if the boinc directory still exists. If it does change its name so you can keep your settings after you get it re-installed.

Try re-installing after deleting all the entries with boinc in them from the registry.

But only after someone who has actually used Windows this century answers as they may well have a better answer!

You can add the groups and accounts again with the net command from an elevated command line.
I'll write it out later on.

The BOINC user groups and accounts are only needed to run BOINC as a service. They aren't needed to run BOINC as not a service.

But in case they are missing, and are inhabiting you to reinstall/uninstall, then follow this BOINC FAQ: https://boinc.mundayweb.com/wiki/index.php?title=How_to_add_usernames_to_the_BOINC_groups_under_Basic_and_Home_versions_of_Windows%3F

Or:
For the newer Windows 10 versions, to get to the elevated command prompt do the following: Search->type cmd->right-click Command Prompt->choose Run as administrator->Acknowledge.
Then do:

    net user boinc_master /add (press Enter).
    net user boinc_project /add (press Enter).
    net localgroup boinc_admins /add (press Enter).
    net localgroup boinc_projects /add (press Enter).
    net localgroup boinc_users /add (press Enter).