How to return administrator rights on Windows 8.1?

Question

Windows

Hello!
There is a netbook with licensed wines 8. Updated immediately to 8.1 and so on, I put all the updates. A week ago, when starting some programs, I started asking for a password:

I immediately (more than a year ago) installed Acronis, and so I didn’t use it much. And now here its user demands the rights. I went into my account, which was administrator, but it is no longer administrator .... I can’t delete anything, I can’t run something with elevated rights .... I tried to create a request on the Microsoft website, but there is the same divorce as on the skype website, they drive you in a circle through the help sections ....
In general, help.
UP#1
There is a suspicion of a virus, not even a virus, but a joke (bad joke) program. I have a bitdefender.
Kureit could not run, requires rights. Launched AVZ, scanned - zero.
Thank you all, the Elcomsoft system recovery professional program helped 10 minutes and you're done

Answer 1

Do you have a local or microsoft record? If the local one pulls a softina like selfinside password.

Answer 2

you can boot from something like MSDaRT, change the password of the acronis account, run compmgmt.msc on behalf of acronis and add your account to the admins, probably like this

Answer 3

Thank you all, the Elcomsoft system recovery professional program helped 10 minutes and you're done