I posted here a while ago with issues uninstalling BOINC. I kept getting the error Failed to delete 'boinc_admins' group. I did try to update that thread but it's now locked.

At the time I re-installed Windows because it was an option, but this time around it wasn't so I delved a little deeper into the issue. After a lot of fiddling around I found it was a mixture of user accounts and registry entries causing the issue. Once I knew what the issues were I was able to google it and found a thread that summarised what was required over on a BOINC FAQ forum.

In summary, this is what is required if you encounter this issue:

1. The User Accounts and Groups To cleanup the newly created users and groups on anything else than Windows XP Home do the following:
Click on the 'Start' button).
Right-click on 'My Computer' and select 'Manage'.
Expand the 'Local Users and Groups' tree node.
Click on the Groups tree node.
Delete the 'boinc_admins' group.
Delete the 'boinc_users' group.
Delete the 'boinc_projects' group.
Click on the Users tree node.
Delete the 'boinc_master' user account.
Delete the 'boinc_project' user account.

Windows XP Home, Vista Home and 7 Home don't have the Local Users and Groups tree node, so here we have to do it differently.
Click on the 'Start' button.
Click on 'All Programs'.
Click on '(Desktop-)Accessories'.
Right-click on 'Command Prompt'.
Choose 'Run as administrator' and confirm.
In the command prompt window that opened, type:
net user boinc_master /delete (press Enter).
net user boinc_project /delete (press Enter).
net localgroup boinc_admins /delete (press Enter).
net localgroup boinc_projects /delete (press Enter).
net localgroup boinc_users /delete (press Enter).

2. Cleanup User Rights Assignments To cleanup the newly assigned user rights do the following (again, only for all Windows version but Windows XP Home):
Click on the 'Start' button.
(Click on 'Settings').
(Click on 'Control Panel').
Launch the 'Administrative Tools' control panel applet.
Launch the 'Local Security Policy' application.
Expand the 'Local Policies' tree node.
Click on the 'User Rights Assignment' node.

Open each user right that contains a boinc_master or boinc_project entry, and remove those from the lists.
Windows XP Home, Windows Vista Home and Windows 7 Home do not have the Local Security Policy. It may be possible that you can remove the entries the installer made from the registry, but it's at this point unknown where it puts these entries in the registry.
(The developers haven't come back to me about this, so I really don't know what the installer does with those entries. Perhaps it silently drops them).

3. Cleanup Setup Registry Entries To cleanup the newly created registry entries do the following:
Launch 'regedit.exe' from the Start\Run menu item.

Expand the 'HKEY_LOCAL_MACHINE' entry.
Expand the 'Software' entry.
Expand the 'Space Sciences Laboratory, U.C. Berkeley' entry.
Delete the 'BOINC Setup' entry.
Delete the 'Space Sciences Laboratory, U.C. Berkeley' key.

Go back to the 'HKEY_LOCAL_MACHINE' entry.
Expand the 'SYSTEM' entry.
Expand the 'CurrentControlSet' entry.
Expand the 'Services' entry.
Delete the 'BOINC' entry, if it exists.

Go back to the 'HKEY_LOCAL_MACHINE' entry.
Expand the 'Software' entry.
Expand the 'Microsoft' entry.
Expand the 'Windows' entry.
Expand the 'CurrentVersion' entry.
Expand the 'Run' entry.
Delete 'boincmgr', if it exists.
Delete 'boinctray', if it exists.

Expand the 'HKEY_CURRENT_USER' entry.
Expand the 'Software' entry.
Expand the 'Space Sciences Laboratory, U.C. Berkeley' entry.
Delete the 'BOINC Manager' entry.
Delete the 'BOINC Screensaver' entry.
Delete the 'Space Sciences Laboratory, U.C. Berkeley' entry.


Exit regedit, reboot your PC, then run the latest BOINC installer.

I have two log-ins, admin and user. I downloaded the latest Boinc, it failed on install as it was trying to update a program file in folder C:/windows/programs files/boinc, tried as admin, same thing. I logged off, logged in as admin. nothing. shut down PC,logged in as admin, still can't delete the boinc folder under windows/program files. I restarted the installation but when I came to naming the folder I changed it to boinc 2 and the installation went through.
my question is would your method remove the offending boinc folder?

No, you will probably have to take property of the folder in question. Tried right-clicking on it to see who all had permission to do anything about it?

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