Hello, those popups should be for you to download and install the new version of Adobe Flash Player which only takes a few seconds to do and yes you need to do it if you like youtube and yahoo messenger, games, etc that depends on it.
If you want to download and install it manually, then you can get it from there website using the link below.
Adobe Flash Player
BEST OF LUCK!GOD BLESS!
Sounds like something else to me. Lets make sure a virus or spyware is not behind this.
1) Go here: http://www.softpedia.com/progDownload/Malwarebytes-Anti-Malware-Download-81598.html
2) Click Softpedia Secure Download (US) [EXE]
3) Download/Save File
Now perform a Full Scan and remove anything founds and also from the Quarantine Tab as well. Finally restart the computer and test it.