SC440 not to recognize SATA Controller

I have a PowerEdge SC440 Server which has been behaving abnormally for about two months. There is Installed Windows Server SBS 2003.

Initially, PCs often lost their connection to network disks and they had to restart the Server.
From a week ago the server accepted Administrator's Windows login, but then remained stationary when loading personal settings without ever getting to the desktop.
Yesterday, the Ctrl-Alt-Del request did not appear and appeared for almost a day "Index reconstruction, please wait ..."

This morning, restarted the machine again, this did not allow login or mapping of network disks.
However, some services started because an application made a job on the Internet and sent the results via email.

In the afternoon the server did not respond to the ping.
Off and on again, it does not recognize the SATA controller in a PCI slot that handles the RAID1 of the two disks.
So now doesn't start even Windows anymore.

We had already planned the replacement of this machine in the coming weeks with a new one and Windows Server 2016, but obviously we have not yet migrated the data and at this point I'm not even sure that the Backups have been successful.

I thought about connecting one of the two disks to a SATA port on the Motherboard. With a RAID1 in theory I should still see the contents of the disk and be able to start Windows.

Dell recognizes the Service Tag, but it does not show me the configuration of the machine and therefore I am not able to say which Controller model is installed.

Finally, the LED on the MB is yellow; if I'm not mistaken, it should be green.

Thanks in advance for any suggestions and help.