Help with full HDD encryption?

DarkDubzs

Honorable
Jun 10, 2013
635
1
10,990
How could i go about encrypting my entire HDD? Exactly how would this secure my data from attackers? Like, if they could physically get my hdd and try to boot from it, would it boot or would they have to enter a key or something? Now something more realistic, lets say i get infected with a virus, will it be able to see all my data in "plain text" or will all the data be senseless? Would viruses still be able to modify my data too? What if i got infected with a RAT? Would the attacker be able to see all my data normally too and modify it? One last thing, if i was to get attacked by CryptoLocker (or something like that), would it be able to "re-encrypt" my hdd or would it encrypt my already encrypted data? How would that work out? So, any help would be greatly appreciated. Thanks.