This isn't just hipster talk when I say this: DO NOT USE INTERNET EXPLORER.
It's ridiculously slow for so many ridiculous reasons. Think of internet explorer as an overly attached girlfriend: so protective it's annoying (and progress can be slow).
Don't ever bother updating internet explorer again.
Firefox is actually faster, and is freeware (the original netscape browser). Trust me, and half the freakin' internet: DO NOT USE EXPLORER.
It just sucks. Period. Ask web developers, software engineers, computer scientists etc.
You have to install adobe depending on what operating system you are using, the browser version you are using, and the java version you are using.
If you are using a x64 bit operating system, make sure you have the 64-bit browser, a 64-bit java software, and a 64-bit plugin for the 64-bit browser. The opposite is true of 32-bit operating systems.
In theory, that is what you should do, but for some reason, 64-bit isn't universal, and many people still use 32-bit browsers on 64-bit operating systems.
What I do:
Install both the 32 and 64-bit versions of java. Download 64-bit firefox. Install the flash plugin. The plugin goes with firefox, it is independent of IE. (Another reason why IE sucks, if you install the plugin for firefox, it should work with chrome, opera, safari etc). Where the google icon is in the top-right corner of the latest version of firefox, there is a drop-down arrow. Click that arrow and change the search engine to yahoo. (I don't know why you would want to do that but that is how, google is the most advanced search engines. So advanced that anyone who doesn't directly work with the algorithms they use don't even know them!).
Firefox has a built-in spell checker that underlines words in red. If you have the bottom info-bar enabled, I think the word error count is displayed there. With regards to the large numbers popping up, I do not understand what you are talking about and cannot help you there.
And with regards to the bookmarks, you should be able to hold as many that fit horizontally across your screen size. The rest are added to the drop down menu AND/OR the bookmarks menu which is very similar to the way IE uses favourites.
I know I am seriously not making a case for myself (and other firefox users) but let me put it to you this way: when the Geek Squad at best buy installed firefox on your computer, they laughed for a good five minutes at the fact that you were using IE that long, and that you actually preferred it.
Believe me, it's that bad. Once you learn how to use firefox better, you will never go back. I guarantee it. In fact, if this wasn't the internet, I would put money on it.
And Adobe will not get you in trouble for downloading a plugin for an additional browser. The software is paid for (it isn't necessarily free) and activated. You can download the flash player a million times if you wanted to and it would all be perfectly legal.
Keep in mind that Firefox, Java, AND the flash player need to be updated regularly. Java automatically checks for updates, as does the flash player. In fact, Firefox also detects and downloads updates, and asks you to install them. You MUST keep all of them up-to-date to keep up with security and patches.
The fact that youtube doesn't work is likely due to an outdated flash player-firefox combination.
You can change your settings in the latest version of firefox by clicking the orange firefox button, and selecting options. Almost all of the options for firefox are found there.
You may enable add-ons and plugins (there is a difference, noted by the different subtitle in the menu) by clicking the firefox button, and then going to "addons".