Hi Athaset, I tend to agree with Ohrenko in this. I have a suggestion that you may want to consider. Firstly, create a new LOCAL user account and grant it administrator rights. Login as that user so it can set the desktop up. Logout & log back in. Next, from an elevated command prompt (right click on command prompt) "sfc /scannow". If it reports errors (corrupt files) and states that it has successfully repaired them, reboot the machine. Run the same command again. Hopefully at this point it will no longer report errors. If it does do the process yet again.
If after several attempts, it is still not happy, move on to the next step which would be to run the command "dism /online /Cleanup-Image /Restorehealth". Usually this will work to clean up some of the windows components.
Reboot yet again and see if the sfc / scannow reports no errors. If errors are reported again give sfc/scannow a final try but by then, I would think a deeper investigation would be required since it would most certainly indicate a deeper problem with the build. You may need to do an inline reset/rebuild of the machine. If all is good, re-attempt installing MP3Tag under the newly created user's profile and see how that goes. MP3Tag certainly does not require XP mode. MP3Tag has always a no brainer install for me and I have installed it many a machine without the issues you are reporting.
If you have ever been inclined to use a "registry" repair tool, that in itself can cause lots of grief, so be forewarned and generally speaking (IMHO) they tend to cause more harm than anything else. Indeed, one very popular cleaner will regularly point to issues with my system. If I allowed the cleaner to do what it wanted, my Foobar installation would get scrambled, my older Office installation (broke outlook) would also get trashed.
I hope that the above provides you some useful guidance