want to add to this thread because it was too complicated for someone of my understanding but I was able to fix it this way:
1) Click Start, type: CMD
2) Right click on CMD, then click "Run as administrator"
3) At the command prompt type "regedit" then press Enter
4. You will see the Registry editor and HKEY_CURRENT_USER
5. In the register base, there will be a "category"/main folder named "HKEY_CURRENT_USER" and you'll be able to browse a hierarchy up to "\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced\". Then the "Advanced" folder should contain several keys amongst which "EnableBalloonTips".
6. Double click and change the value from "0" to "1"