X51 R2 goes randomly into power save mode and then takes several tries to manually restart

what do you meen by "it takes several tries"? what happens there?

My X51 started just randomly going into power save mode

You mean Sleep? Is the Power-Light on x51 actually indicating that mode? Or, is your monitor just going to sleep (due to no-signal from locked-up computer)?

Hi DarthMaleval‌,

Try running an ePSA/Diagnostic test on the system, click here to view a Dell article that explains how to run this test. Let me know if you receive any errors. 

After it goes to power save mode, it stays that way.  It's kind of like when it sleeps, but the mouse and/or keyboard have no response and I normally have to shut it completely down.  After that, when it restarts...it will go right back into power save mode before the boot process.  Then I'll have to repeat that again.  Eventually after a while it will decide to boot up normally.

probably Overheating Protection.

as Alienware-Eimy wrote, run the EPSA Test first and then we will see.

Ran the ePSA test....no problems.

unfortunately i still believe that it has a Hardware Issue.

it could be the Video Card slowly failing. first Thing you can try is pull the Power Plug, open the X51 Case and remove the Video Card. connect the Monitor to the Port on the Back of the X51 and try to run your Machine with the Intel GPU. tell us how it goes.

When I get some time, I'll have to try that. 

Here's the other odd thing about this....after it goes to power save mode and I manage to successfully restart the computer, it usually never happens again (as long as the computer isn't shut down or put to sleep).

It usually happens after the computer goes to sleep or is shut down normally.  I had to change my settings for it to not go to sleep, otherwise it won't wake up.