Hi,
If you are using WordPress 2.5, then you can go to the Design Tab, and click the Theme Editor button, and click on the stylesheet. Inside the stylesheet, if you know CSS, you can change your styles so that your links are always blue.
If you don't know how to do this, you could just add this code to the bottom of your stylesheet:
a {color: }
a:active {color: }
a:hover {color: }
and after "color" just put the code for the color, preceded by a number sign (#).
You will find the color codes here: http://html-color-codes.com/
If you are unsure, please e-mail me at info [at] kulpreetsingh [dot] com and i'll be happy to help you out individually in more detail.
As for the video code, if you are copying the code from YouTube, you should insert it in the HTML part of your post, not the wysiwyg editor.
-k.s.