To install Windows 7 from pen drive instead of DVD.

The source DVD must be in ISO format.

To turn a CD, DVD, stick or file into ISO, download the UltraISO program. It's for a fee, but it gives you some free trial.

To create a bootable USB pen drive for Windows 7 from DVD:

you need to download this small program

Windows USB/DVD Download Tool

A bootable USB stick is useful for many applications:

•     install a Windows10 operating system
•     install a Linux operating system

Windows 10

Download Media Creation Tool from Microsoft website

Linux

Download Rufus or UNetbootin

FREE.Complete PDF management. Merge, separate, unlock...

There are many online programs that manage pdf files and convert pdf to various formats: jpeg, Word, Powerpoint, txt. Almost all of them allow you to drag the file directly into the online window, but:

•  some work only for a few conversions and then ask for money 
• others are complicated to use
• others have few functions 
• others work badly 

I tried a dozen of them and I found the best one.

This "online2pdf" program is extraordinary both for its many functions and for its extreme user-friendliness. Just drag the file(s) into the online window and you'll quickly get the conversion you want.

It's free, it's online and only suggests you a small donation if you want it.

You can find it at this link:

https://online2pdf.com  

I do not dwell on the functions and mode of use because it is completely intuitive. You can't go wrong. You can find all the instructions on the site.

It even has 10 functions. Certainly more than you can imagine:

• Conversion to PDF (also several files separately)
• Conversion from PDF to Word, Excel, Powerpoint and other formats
• Merge files
• Extract pages, rearrange pages or split files
• Rotate PDF pages
• Unlock PDF & remove password
• Define header / footer
• Compress PDF & reduce file size
• Set or customize PDF layout
• Protection & some more preferences

Conclusion: the best free online program for PDF management.

Which SD to buy? What are the fastest SD?

Here is the list, from the slowest to the fastest updated in October 2018

Just read the abbreviation on the card.

SD : the oldest. Capacity from 128 MB to 2 GB Format FAT 16

SD HC Capacity from 4GB to 2 GB Format FAT 32

SD XC Capacity from 64GB to 2 TB Format exFAT

SD HC I - SD XC I It is an SD spec. 3.0 very fast, suitable for 1080p

SD HC II - SD XC II It is an SD spec. 4.0 very fast, suitable for 4K

SD speed class

2 = 2MB / s

4 = 4MB / s

6 = 6MB / s

8 = 8MB / s

10 = 10MB / s

UHS speed class

1 = 10MB / s

3 = 30MB / s