After completing my work, I chose the update and restart option. But then i got a blue screen of death with the code - inaccessible boot device.  I have tried every option from Windows recovery environment, but cannot solve the issue. Hence, the only solution is to reinstall windows. My question is three folds.

1.  I want to use the dell windows recovery tool. But I'm not sure what affect it will have on data. Currently, I have 4 partitions  in my hard drive i.e. C,D,E and F. Windows is in C drive. So when using this tool, will I still have all my partitions as it is or will the process delete all the partitions and all the data in it? I want to install OS in C drive so that my other data is safe.

2. If I create a bootable usb device using windows media creation tool, will it ensure that my data in other drives is safe? Since it gives the option to chose the partition where you want to install your OS? 

3. What is the difference between Dell OS/Windows recovery tool and downloading/installing windows from Microsoft website using bootable usb? Which method should I prefer for my problem?