No if the the inspiron system is a few years old.
Then your likely first cause to the system shutting down may be due to a faulty power supply or one that is beginning to fail on you due to age.
Dell are not known for fitting quality power supply units to there pre built systems, and are often a cheap affair of power supply units that in my experience start to become unstable and faulty after a year or two of running.
After all it is the main component of any Pc so if it develops a fault and is becoming unstable at providing the right voltages to the rest of the computer it will result in frequent shut down and powering off of your system.
The only other thing I would check is for dust build up of the cpu heat sink and fan solution of your Inspiron, see if it is not clogged up with a thick layer of matted dust build up, if so use a soft small paint brush to clean all of the dust out.
Also check that the fans are in good condition and are spinning when you power your Inspiron tower up.
If broke replace the fan or fans with new working ones.
The other cause. info on why.
If your cpu overheats the tower or system will also auto shut down and power off to protect any damage to the cpu.
So you should check like said all the fans are spinning and remove any large build up of dust of the cpu heat sink sitting at the top of it between the cooling fan.
A faulty hard drive would not cause the system to power of after 30 seconds to it being powered up.
The cause is ether a bad power supply or overheating causing the system to shut down over a short period of time running.