I received an email that appears to be in HTML, it's a long keysmash-looking bunch of text?
HTML is easily readable. Random characters is more likely binary data. Also, emails don't have IP addresses in them usually.
That "shJsdjAdKJSisajjffkS" is NOT a common base-conversion issue, nor is it HTML/URL encoding, nor is it "keysmash" (I like that... I think I'll use that.) It looks a lot like a standard encryption. If it is, doesn't really matter to you. Regardless of all that, if you don't know what to make of it... delete it, and definitely don't click any links in it. Keep yourself safe.
What you are seeing might be a program that was meant to corrupt your computer. Delete it now. I hope you haven't clicked anything on it or else... Reformat and reinstall everything from scratch.
jcastro: It could be encoded in base64: https
It could be encoded in base64: https://en.wikipedia.org/wiki/Base64 Find a base64 decoder in the internet, and use it.