Does the MBR option from Rufus delete your data when installing Windows?

I'm trying to install a Windows on an old computer and for that I'm using Rufus to create a bootable USB. I used the defaults properties from Rufus and clicked start. This action was successfully made, but when I tried to boot the USB in order to install the Windows, it appears me a screen with some dots instead of the launching installation pop-up.

After a search I found that someone has the same problem, so he was recommending to select MBR instead of GPT from the Partition Scheme property, but I saw some comments that warns us that I will lose my files. Does the MBR cause the delete of my data if I have multiple partitions? In other words, it will delete only C: or also D: and E:?

Technically, no. The partitions are never deleted automatically, no matter which option you choose. However, I suspect that those comments are talking about something a few steps ahead, where it may seem as if you end up being forced to manually delete partitions.

Selecting "MBR" for the USB stick isn't actually the main point. The important part is the "Target system" choice – if you choose MBR as the USB stick's partition scheme, it'll result in the USB stick being prepared for BIOS-mode boot process (as opposed to UEFI-mode boot), and that's where the main difference lies.

(As the USB stick doesn't have full GPU drivers, it uses the firmware-provided video output to display stuff on screen – and apparently on your computer this doesn't work completely right in native UEFI mode, but does work in BIOS-emulation mode. This isn't very surprising for old computers; they had mediocre UEFI implementations for a while.)

However, whichever mode the Windows installer is booted in will also be used for the final installed system. That is, if the USB stick was booted in BIOS mode, then it will want to install Windows to always boot in BIOS mode as well, and the same for UEFI. On top of that, Windows also wants the system disk's partition table to match the boot mode – BIOS systems typically use MBR for the system disk, while UEFI systems normally use GPT.

(In short, this is what you end up with:
MBR for USB stick → BIOS mode for USB stick → BIOS mode for installed OS → MBR for system disk)

So if you're booting the installation USB stick in BIOS mode, but your system disk was previously GPT-partitioned (it had an UEFI-mode installation), then the Windows installer will generally refuse to do anything with it – it will only allow installing to an MBR-partitioned disk. (And the same happens in UEFI mode if the disk was MBR-partitioned, the installer will insist on it being GPT-partitioned instead.)

The problem is that the built-in tools that come with Windows (i.e. DISKPART) only support converting empty disks between GPT and MBR. So if the Windows USB stick is literally only thing you have, and if the graphical installer is the only thing you know, there is no other way to proceed – to the commenters, it probably seems that in order to do a BIOS-mode install you have to delete all partitions first and let the installer convert the now-empty disk from GPT to MBR.

(Note that the partitions are not deleted automatically; the installer just won't continue instead.)

In this case, the way to avoid this is to boot from a Linux USB stick first, and use the gdisk tool which can in fact convert a disk with partitions between GPT and MBR formats. (Though converting to MBR isn't always guaranteed to work and gdisk might refuse to do that.)

Though if your system disk wasn't GPT-partitioned previously (i.e. it just had MBR and a BIOS-mode Windows installation before), then there's no problem anyway – the installer will just accept the disk as is.