Hello Sir

Real tek PCI: PXE-E61: MEDIA TEST FAILURE, CHECK CABLE, PXE-MOF: EXITING PXE ROM. REBBOT AND SELECT PROPER BOOT DEVICE OR INSERT BOOT MEDIA IN SELECTED BOOT DEVICE

I was facing the above problem and have tried everything that you mentioned. Next day again the same problem persisted and I repeated the steps you had mentioned. 

After running Diagnostics it  mentioned no problem...all tests passed

Now I get the message No Hard Drive detected

After running Diagnostics again Windows starts.