So other than noticing this strange icon. What have you done to determine what it might be?
Have you run antivirus and malware programs?
If we know what you have already done we can suggest other options.
This may be an icon or font problem. In the start menu and to the right of menu items where there would normally be arrows showing that there are submenus, I have no arrows but rather a strange figure that looks like a firecracker -- a cylinder with a curly string attached. This problem also exists in many programs that have menu lists. Also the scroll bars in most programs do not have arrows but other strange icons. For example, the bottom scroll icon is not an up arrow but instead an hour glass. Thanks in advance for any help.