A few years ago there were some malicious Electrum servers broadcasting a message to Electrum users directing them to download and install a malware version of Electrum. The malware wallet would send all the bitcoin in the wallet to the hacker's address whenever the user made an attempt to send ay transaction. I don't know if seed phrases were compromised by the same hack, but that certainly could have happened.
That's right. But I didn't have any problem with transactions to\from the wallet - everithing was Ok
I would suggest you start from scratch; fresh OS install, fresh Electrum install and make sure to
verify the download before installing it, and then create a new seed. Write the seed down on paper, and store it in a safe place. Don't store the seed digitally, and don't store on any cloud servers.
It's clear. I gonna create a new wallet. But I won't can change settings of some stations which send BTC to this wallet's adress because no access to them right now. I'm unable to make sure if someone else has access to my wallet, am I right?
As I already
noted I've checked my exe's with GPG