That reads as if your mechanical disk isn't getting mounted at system start-up. Check your /etc/fstab. The system might try to mount the disk using a...
The top or htop commands will show you, by default, which processes are using the most CPU. You can hit F6 to sort to it by this value or "CPU_TIME"...
So far I have installed 24.04 on 14 different computers and had a similar problem on one of them ("no camera found"). I offer this not as a solution...
I have a dual boot system with three HD.
Two of them are solid-state HDs, with Ubuntu 22.04 (root and /home) on the first and Windows on the second....