Hi,
You can confirm this thing by giving this command " sh post" and " sh power inline status"..
If it is any problem with hardware, POST result will give the status of the same (i,e Power inline disabled and the corresponding test was failed)
As well as if you are restarting the same switch, you will get the same in the logs (sh log) also..
Then you have to go for RMA...
Thaks&Rgds
Senthil