Upgrading a Precision 3620 (RAID1) from windows 7 to windows 10

Some time ago, I purchased a Precision 3620 with a RAID1 option, a Windows 7 “downgrade”, and the MSO Home edition. I am now ready to upgrade to Win10 (the system is licensed for Win10) and I have the Dell Windows 10 DVD provided with my machine. I would really like to avoid doing a clean install so that my current file organization is preserved. The best I can tell, the Dell DVD does not offer that option ... or maybe I’m just not smart enough to find it. Further complicating matters is a message that I get from the BIOS when I attempt to set it up as Indicated on the DVD sleeve. The BIOS message indicates that such a setting could cause the RAID1 array to cease to function and require a clean install. Is there anyone who has been able to successfully upgrade the OS within the stated hardware environment?