Reportcheck.xyz is a new malicious domain currently involved in scaring many users with a lot of really frustrating information. The pop-up typically appears through your default browser. The chances are that the reasons for such pop-up windows are concealed in the presence of certain adware inside of your computer.
The domain name airmusical.xyz is actively involved today in massive distribution of various scary alerts through all major browsers. These pop-ups are powered by certain adware or browser hijacker, which has recently become the part of your computer. In order to get rid of such pop-ups you will need to find the program causing these scary alerts in your browser.