Windows 7: micro view on 2 sites only. why?

Running windows 7 on a dell laptop since 12/09. While composing an email in Yahoo mail I hit some combo of keys, by accident, that shrunk the font to almost invisible., but only on Yahoo Mail and the other window I had open at that time, My eBay Summary. All other Yahoo and eBay pages display correctly. All other sites appear normal. Tried display & fonts in control panel but nada. Microsoft Geek squad has no answer. Looks the same running explorer or firefox but only those two places.

So if you close your browser all together and re-browse to the compose e-mail screen, the font is still tiny?

yes, and several folks with more computer know-how than I are stumped. My desktop works as usual, normal but this laptop has me going blind on those two site selections which were the only ones open when it happned

In any window, can you type about:config and hit go (enter)

Look for the font.size.fixed and font.size.variable values, are any of them smaller than the standard (my guess) 16? if so, go ahead and change them and try to view the page again.

font size fixed shows all but one as default, some 13 most 16. one says user set and is 14 i will switch that to 16. In variable one is user set at 22. should i set that to 16 also?

I tried resetting the 2 that said user set as opposed to default bu still small type on both tiny windows.