Right, be sure your "personal data files" are backed-up (a couple of different ways is good). You know, you can always make another copy ... just "file copy" them to a USB flash-drive in Windows Explorer. Shut-Down, power-down, un-plug from wall, dissipate flea-power. Remove or completely disconnect both existing internal drives. Main thing I wanted to mention ... do NOT buy another spinning-platter HDD. Get yourself a good 2.5inch SATA SSD (like this one). They are much faster and more reliable than any HDD. Clean install Windows to the new SSD. It should now be the C-Drive, and hold and boot Windows. The faster booting and program-starting should help since machine is older/slower than newer ones. Note: DO NOT re-install Intel-RST. You DO NOT want Intel-RST ever again. Windows-10 has native HDD/SSD drivers that work perfectly fine. After all that is working, you should be able to reconnect your old Toshiba HDD (and use it as a data drive). It might have to be erased first. 
Hi, I have a Dell XPS 8900 that is fitted with a samsung ssd cm851 m.2 2242 32gb used to speed up access. The Windows 10 operating system is on a separate internal hard drive.  The 32GB SDD has failed. I have my personal files backed up via WD backup on an external drive and they are also on the internal hard drive which was still OK according to the tests I ran when the SDD first showed signs of failing. I no longer wish to use SDD disc acceleration and would like to re-install Windows 10 on a new internal hard dive and use the existing internal hard drive (on which Windows is currently installed) for data storage. Can anyone advise how I can achieve this? In particular I am not sure about the following: 1. What do I need to do to disable the cache operation? - I presume I need to do this before I reinstall Windows. I accessed BIOS on booting using F12 but did not see an option to disable acceleration. 2. Once I have installed Windows on the new drive, if I then fit the original drive will I still be able to access my personal files directly or will I need to recover them from the backup I have on the external drive. Also, should I remove the Windows files from this drive. My hardware and setup according to the IRST app before failure was:Toshiba DT01ACA200SATA hard diskStatus: normalUsage: accelerated diskAcceleration mode: enhancedSamsung sdd cm851 m.2 2242 32gbType: sata solid state driveStatus: at risk (SMART event)Usage: cache device Thanks. Mark.
XPS 8900, failed SSD cache