Hello. I don't know how to explain this. But a few months ago, all the websites I load on Firefox were fine. But its been a month that all the websites are like messed up. The thing is that if I want to login to Yahoo Mail, the login bar and the password bar is tiny. And even if I type anything, it won't show what I am typing. I don't know what is wrong. IE won't even open the whole website and Chrome is also messed up.
You can also Try to start Firefox in Safe mode. This mode disables all extensions, user customizations, hardware acceleration, etc. temporarily for diagnostic and troubleshooting. If Firefox works fine in Safe Mode, then this is likely an add-on issue. Restart Firefox in normal mode, then type "About:addons" (without the quotes) in the address bar. Disable your extensions one by one, restarting Firefox between each one, until you find the trouble maker. Once you do, you can disable that add-on and report the issue to that add-on's developer.
A few other basic trouble shooting things you can try is this:
Run all Windows Updates, install all needed service packs, etc.
Download and Install MalwareBytes Anti-Malware, run a full Scan. http://www.malwarebytes.org/. This helps check that there are no viruses on your computer causing issues. You can uninstall this program after you clean off any infections.