Since i cant even see what you are talking about and since you have not told me everything that you have tried i cant give you a "press the blue button and it will work" If one of those was out there you would have found it already. What will definately work. RE install the program.
are you talking about firefox or thunderbird ?
and can you please send me a screen shot of what you are talking about. That will make it a lot easier for me to figure out what is wrong and thus how to fix it. Would you tell your mechanic "my car engine works wrong how do i fix it i already tried everything" and refuse to answer any questions about what happens when you turn the key or press the gas or what lights are on because "you already checked those and they dont matter"
Screen shot instructions
hold alt button down hit print screen button release buttons
click start menu / all programs / accesories / paint
click edit / paste
click file / save as
save as a jpg file in my pictures
on the top of this window click the insert button it should be a paper clip to right of the smiley face.
click browse in the 2nd window that pops up
browse to the file you just saved in my pictures
click insert back in the first window