Why am I having problems with my browsers; Firefox and now Internet Explorer?

[JEN MYOB]

They are different problems, year ago my clients started telling me they weren't receiving my e-mails & noticed my Adobe suite wasn't working properly so switched to Internet Explorer against advice from friends who said IE bites. So this Sunday noticed change in my main e-mail account w/at&t Yahoo there were no more boxes by e-mails that allow me to chk & delete any e-mails. So on to my Ya! sub-account for my biz needs, can't attach document for a client there's no paperclip option to add attachments. Presently on Chrome for needs.
Does this have to do with Compatibility View settings? IDK, but I would really like to make some sense outta this nonsense. At&t support was useless, he just told me he couldn't fix it & to move over to Chrome.
Anybody know about these issues w/solutions? My computer knowledge-base is sub-average so please be at 101 level on what to do next. Ty!

[Carling]

It would have been nice to know what windows your using. But my answer would have been the same anyway Your problem is NOT firefox It IS your operating system (Windows) What ever version it is, You have been using answers has long as I have so your not new to computers, I stopped using windows 12yrs ago for many reason, It's never been stable or secure, You have been using firefox which is a Linux web browser, Chrome Chromium and Android are other Linux web browser,

It's time you learned that Microsoft and Mac or not the only computer operating systems in the world There is another one that's Free, Faster, Stable, Secure, and far more advance, It don't crash, freeze up or gets viruses, it's up to date March 2014,

If you would like to know more you can message me. I can't message you because you have not setup answers to except messages from other answers users, In the mean time take a look at this website it will show you what Linux operating system runs and works like, it works like Win Xp, and W7
http://zorin-os.com