Wy are all my Yahoo groups in a font so small I cannot read them?

Several months ago wile using a WiFi connection Saudi Arbia all my groups became unreadable with a font about size 1 or so. Why did that happen and how do I fix it? I am using Vista on a new VAIO PC & everything I do is screwed up to say the least & if MS would restore service for XP I would just go back to the product that works. I do not know if this is a Vista related problem or a hardware problem. This VAIO most certainly is a apiece of crap as well.