VMC runaway

Well after years and years of service I'm running into my first post build big issue.
Today it seems as it's just locking up. Monitor freezes, no input from devices functions. Mill continues to just travel in the direction it was going which luckily did not get overly exciting.

So I'm thinking the PC is just dieing. I can restart it, run it, works for a bit.

First time it did it while I was setting tools so it wasn't in an active program. It has done it twice in an active program while running a boring cycle. So it's out of service now.

Does anyone have any idea of what could be causing this or ways to troubleshoot.?

This was an older computer 6 ish years ago.

It is a Pico PPMC controlled machine.
Kinda crazy that I would have though a lost com from the computer would have resulted in stopping the machine.

Next question.

Building a new computer what's the hot ticket for best machine to build with.

@Jake
I would start by disconnecting and reconnecting any plugs and connector few times to clean the contacts. Since the ppmc uses edge connectors, clean the edge connectors following this method:
1: Clean the contacts with alcohol and cotton swab/Qtips, let dry.
2: Use Rubber eraser to clean contacts (one pass up/down on each individual contact).
3: Clean one more time the contacts with alcohol and cotton swab/Qtips, let dry.

If the above does not do the trick contact JMelson.

Now that I think of it, the first lockup occurred when I was setting tools and dropped the pendant. I'll start there. Hopefully I didn't hurt it.

I'll go through and clean all the USB connectors on everything and try it. I'll try it with it up and clear of everything.

One more question, anybody have any ideas on how to prevent the lockup causing a crash? I got lucky the feed rates were low. You know it when there is a 3/8" end mill buried 3/4" deep in a piece of mild steel

Thanks Andy,

That is what I thought was supposed to happen, it just continues on with it's current trajectory.

When it did it the second time it was in a boring cycle. Going round and round and spun out of the circle.

A USB storm does make sense as it did it after the pendant was dropped.

Update...

I cleaned all the connectors yesterday and ran the machine. Ran like normal.

Looking back at when it did this I had a USB flash drive plugged into the USB port on the control panel. It appears that the drive is cracked. I think I have a smoking gun there, new lesson learned on this I do not think I will run the machine with a drive plugged in. I gotta get caught up and get the tool changer working, and maybe try out GMOCAPPY.