CDROM.SYS appears to be corrupted - have tried all previously recomended solutions

CD/DVD driver no longer working - Device Manager shows ATAPI iHAS122 F with a code 39. It was working the previous day, there have been no Windows updates or other changes I know of.

I have tried the following fixes:

1. Uninstall the device and restart
2. Restores to all available restore points
3. Uninstall the device, shutdown, fully disconnect it, restart, shutdown, reconnect it and restart.
4. DISM checkhealth, scanhealth and restorehealth. restorehealth seemed to have run successfully but it made no difference.
5. msdt.exe -id DeviceDiagnostic did not fix it (but along the way it prompted me to turn off the blocking of driver updates)
6. REGEDIT to remove upper and low filter properties on HKEY_LOCAL_MACHINE/SYSTEM/CurrentControlSet/Control/Class{4D36E965-E325-11CE-BFC1-08002BE10318} but they weren't there in the first place
7. REGEDIT to add a new key to HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\atapi
8. Deleting or renaming CDROM.SYS ... it won't let me do it.

sfc /scannow showed a lot of corrupt files in the CBS log but most were repaired... but not the ones related to CDROM.SYS. Messages like:

Warning: Unable to repair payload file ([l:9]'cdrom.sys') for component ([l:75 ml:140]'amd64_dual_cdrom.inf_31bf3856ad364e35_10.0.26100.1150_none_1ebb5f5f4fbeada4') from backups directory with disposition (2). A backup file may not exist or may be corrupt. Falling back to WU.

and

CSI Payload Corrupt (w) (Fixed) amd64_dual_cdrom.inf_31bf3856ad364e35_10.0.26100.1150_none_1ebb5f5f4fbeada4\cdrom.sys

and

Repr: Not able to find replacement file for component amd64_dual_cdrom.inf_31bf3856ad364e35_10.0.26100.1150_none_1ebb5f5f4fbeada4, file cdrom.sys from any local source

and

CSI 000003ee [SR] Cannot repair member file [l:9]'cdrom.sys' of dual_cdrom.inf, version 10.0.26100.1150, arch amd64, nonSxS, pkt {l:8 b:31bf3856ad364e35}, type [l:14]'dualModeDriver' in the store, hash mismatch

seem relevant. There are more like this.

In W11, CDROM.SYS is in

:\Windows\System32\drivers\cdrom.sys

mine is definitely there, dated 19th Dec 2024.

I don't think it is a hardware problem. I have a secure USB storage key which seems to present itself as a CD drives and uses the same ATAPI iHAS122 F driver and that exibits the same issues in Device Manager when plugged in. It works fine in another computer.

I am at a bit of a loss now. Any help would be appreciated