I am having an intermitient issue where I am losing my E drive which is a SATA hard drive. If I reboot then the drive will re appear. Also the PC freezes up from time to time. The PC is only 2 years old. Could the power supply be causing these issues?
Potentially, but if it was, it would affect other things. The freezing is probably a side effect of your hard disk disappearing. Make sure the HDD's cables (Data and power) are connected securely, if the issues recur, try using a different data cable if you can, and plugging the drive into a different slot on the motherboard (if you have another spare)