Software Process Explorer "Replace Task Manager" function randomly cancels itself (Windows 7)

I made an account just to ask this question. I've been having this problem for a few years now and I'm finally sick of it.

I use Windows 7, and I've used Process Explorer in place of Task Manager for as long as I can remember. In the past few years, it's suddenly decided to randomly revert to standard Task Manager. I have spent longer than is reasonable trying to find any sort of cause, but as far as I can tell, it's completely random. One day it'll bring up Process Explorer like it's supposed to, the next day suddenly Task Manager shows up instead. I open up Process Explorer manually, and the "Replace Task Manager" option has been unchecked.

I am the only one who uses this PC. I am the only one who even lives here. I built this PC from the ground up (I'm talking "power tools and soldering iron" built, not "screwdriver" built) and it's been running fine for six years. So the only explanation I can posit is that my cat turns the PC on and unchecks it while I'm not home just to mess with me. I'll...let you decide how likely that is.

I have spent hours on multiple occasions searching for a solution, but I have never found anyone asking about this anywhere at any point. It's really started to irritate me, because when I open Process Explorer, it's usually important.

I strongly doubt it's relevant, but I might as well slap my specs here anyway.

Windows 7 Professional 64-bit
AMD Phenom II X6 1100T (overclocked to 3.5 and undervolted by .375)
16 GB (4x4) DDR3 1333 CL7
ASRock 990FX Extreme9 (northbridge overclocked by I forgot but it works)
ASUS GTX 970 Mini (because my power-hungry dishwasher suffocated my Nano to death yes I'm still bitter wanna fight about it)
Corsair TX750W
6 drives, 3 hard and 3 solid
And just to be unreasonably thorough, there's no way it's overheating. Just...trust me on this. This thing is completely ridiculous.

I'll be busy today, so I won't be able to check back until later tonight, but I really appreciate any input.