Checking checksums with HashTab
What's the point of checking checksum ?
To find out if the file you've downloaded isn't changed, corrupted, etc.
1. Download it, and install.
2. RMB the file you want to check. Choose: "Properties".
3. Now choose "File Hashes" tab:
4. Checksums will be automatically calculated. Cancel it, and click: "Settings":
5. Choose checksums you want, need:

Most popular is MD5 (although not 100% safe\sure). SHA "family" is used by "security aware" people (DC download page provides SHA-1 checksums), most often the second "generation" (SHA-256 - 512).
6. Now paste checksum here, and await for results:

If it's correct, you'll see that green sign.
Burning .iso file\image to a CD\DVD with CDBurnerXP
Why use CD\DVD instead of pendrives ?
Cheaper, safer, and compatible with older computers while booting.
1. Download and install it.
2. Run it. Choose this:
3.
A - browse for the .iso file\image you want to burn.
B - choose your burner. Be warned - if you have a virtual drive, it could show up here too, so take care.
C - choose burning speed. If you're using a good quality media, you can leave it as it is. If not, take it down a notch, or two.
4.
If you don't know what other options do, leave them as they are, and click: "Burn disc".
Creating a bootable pendrive with Rufus
Why use bootable pendrive, instead of CD\DVD ?
Faster loading time, some computer don't have CD\DVD drives.
1. Download it.
2. Plug in your pendrive(s), run Rufus.
3.
A - here you can choose which pendrive use.
B - for greater compatibility choose this setting.
C - if you're using that pendrive for some time, it's better to test it for defects.
D - quick format to "clean" it of any leftover data, etc.
E - from this dropdown list choose "ISO Image".
4. Click this, browse for .iso file, image you want to use:

Rufus could change some setting, but don't worry about it.
5. Globe icon on the right, changes language.
Click the "Start" button at the bottom:

Depending on your pendrive speed, settings you choose, .iso size, etc, it could take 10 minutes or more. After it finishes, Windows probably won't be able to access it, but don't worry it will* boot. And if you want to use it like before, for data, whatever, just plug it in, run Rufus and quick format, while unchecking other options.
Booting your computer with LiveMedia
Why boot your your computer with LiveMedia ?
If you mess things up with DC, and you won't be able to start your computer normally, it will allow you to boot it into a "bare necessities" Windows 7, and un-mess.
Also using a LiveMedia to encrypt, is safer, and recommended.
1. Locate your computer on the following list:
http://i.imgur.com/FILt1Hl.jpg2. Look at the: "Boot Menu" column.
3. Put\plug the LiveMedia you've created before into your computer. Reboot it.
4. Keep pressing the key you located in step #2. Choose the device that hosts your LiveMedia. Press "Enter".
5. You will boot into a stripped down Windows 7. Use included DC to un-mess the mess you did with DC (decrypt, change bootloader config, etc.).