How do I delete a Bitcoin full node from my hard drive? I was using Bitcoin Core as my wallet (recently installed), but a couple of hours of syncronizing, all of a sudden, I have no space at all in my hard drive. I deleted bitcoin Core, but that did nothing. What files do I need to delete?
Before you delete you Bitcoin data from your hard drive, ensure that you have backed up the wallet.dat file, or you risk losing your bitcoins in case you received them on the addresses generated by Bitcoin-Core.

Ubuntu

The most easy way to remove Bitcoin-Core from Ubuntu is by running: 

sudo apt-get remove bitcoind. 

When you run bitcoind, it typically (by default) creates a .bitcoin directory in the home directory of the running user unless you have explicitly specified the datadir to where the software will download the blocks and other data. If you're not sure where this path is, you could run the following command to help find it: 

sudo locate .bitcoin. 

After finding the path you can purge the entire directory by running the command: sudo rm -rf /path/to/.bitcoin.

Windows

Navigate to Start --&gt; control panel --&gt; programs and features and scroll down the list to where bitcoin core/bitcoin-qt is listed, right click and click "uninstall or change a program" and then try uninstalling it that way.

In Windows, by default the block data is stored in the directory C:\Users\your_username\AppData\Roaming\Bitcoin. If you want to delete the entire existence of Bitcoin blockchain from your machine, you can delete the entire folder. 

Finally, run regedit (win + r -> regedit). In the search, enter bitcoin and delete all entries matching the list.