No, now your roommate has to pay the hacker $1,500 for the decryption key

You don't have to pay them, someone else can get it decrypted if they're experienced. Even if the op had a password they can still unlock it then encrypt it

How'd the backups get encrypted? Did you leave the external drive plugged in? When it comes to backups, always make sure that you have one that is airgapped - meaning that there are no physical connections to anything unless it's in use, and that it's not possible to connect to wirelessly. I'd recommend investing in a large capacity USB. You can easily find one as large as 500 gigabytes for around $150, which isn't bad, considering the size to storage capacity ratio. It's basically a pocket sized small external hard drive. Back up your most important files on it regularly, and always keep it on your person when not updating or retrieving files from it.

Yeah right liar

Cloud storage. After a hard drive crash, I keep all my thesis related stuff there.

Even with up-to-date virus definitions, it's still possible to have your device become infected. It's impossible to keep up because for every type that is recognized and screened, more are constantly being made that find any possible exploits. Your best bet is to have multiple points of protection: not only an anti-virus program, but also browser plugins, clean up applications (like spybot, not the spam ones), and sensible habits. Avoid any sites with unsigned or out of date certificates, never follow links unless you're absolutely sure of the identity and intent of the sender, don't click ads (even on reputable sites as not all of them thoroughly check the ads they host, if they check them at all), and don't open e-mails unless you're certain of the identity of the sender (and be especially careful, as the from line is rather easy to spoof, and some spam e-mails include official looking logos).

ransomware is not that hard to get around really. don't pay them anything ^.^

Take it to a computer shop and they might be able to help you get your needed info off there and at least make a hard print of it. I'd also make your roommate pay at least part of the fees for causing damage to your property. You could also try asking the professor of your school's computer division if they can help you get your dissertation off the computer. Paying the ransom isn't going to do anything except mark you as a target for in the future, give them your bank account information, and the chances of them not leaving a way to re-access your computer is minimal. IF they even decrypt your computer instead of taking the money and running. I'd also suggest bringing up what your roommate did and your information being held ransom to your teachers, as well as file a complaint against your roommate, given that he danger your property, accidentally or not. Paying the ransom is a dumb idea all around, unless you have the cure for cancer on there. If push really comes to shove and you can't get your dissertation off there without paying the ransom, I'd say you're better off not paying the ransom because of how much it could worsen the situation. I'd also make sure everyone on campus or even remotely involved with them knows that your roommate is an asshole who will **** up your computer doing stuff on it that they don't want to do on theirs, and will then leave you to suffer the consequences. They should find themself paying socially for their assholery even if physical or financial repayment doesn't happen.

You can remove the ransom ware and then do a recover of the hard drive for deleted files. I had that work like twice

Make him pay if he doesn't take his ass to court