You're mid-task, and the screen freezes. Or you get a Blue Screen of Death with a random stop code like MEMORY_MANAGEMENT or IRQL_NOT_LESS_OR_EQUAL. Then it reboots, works for an hour, and does it again. I've seen this a hundred times—a client's office PC would crash every time they opened a large Excel file, and we found one bad stick of RAM causing it.
Let's fix it. Work through these steps in order. Stop when the problem goes away.
Step 1: The 30-Second Fix – Reseat Your RAM
This sounds too simple, but it fixes more random crashes than you'd think. Dust, thermal expansion, or a slightly loose stick can cause intermittent contact issues that show up as random freezes.
- Shut down the PC and unplug the power cable.
- Open the case. Touch a metal part of the case to ground yourself.
- Locate the RAM sticks. They're long, thin boards with clips on each end.
- Press the clips outward until the stick pops up. Remove it.
- Reinsert it firmly—push straight down until the clips click into place.
- If you have more than one stick, reseat all of them.
Power up and see if the freezes stop. Had a client last month whose entire print queue died because a RAM stick had worked itself loose after a desk bump. Thirty seconds of pushing it back in fixed everything.
Step 2: The 5-Minute Fix – Run MemTest86
If reseating didn't help, it's time to test the RAM itself. MemTest86 is the gold standard—free, boots from a USB stick, and checks every memory location for errors.
You'll need a spare USB drive (it wipes it). Here's the short version:
- Download MemTest86 from
memtest86.com(the free version is fine). - Use their USB installer tool to write it to the USB stick.
- Plug the USB into your PC, boot from it (usually F12 or Del during startup).
- Let it run for at least one full pass. That takes 20-30 minutes for 8GB, longer for more.
If you see red lines with ERROR messages, you've got bad RAM. The test will tell you which stick (e.g., Slot 2 or DIMM A2).
If it shows zero errors, RAM is probably fine—move to Step 3.
One tip: if you have multiple sticks, test them one at a time to isolate the bad one. But if the test errors even with a single stick in the same slot, that points to the motherboard slot.
Step 3: The 15+ Minute Fix – Test Motherboard Slots
MemTest86 passed, but you still get crashes. Or it failed, and you want to know if it's the slot rather than the stick. Motherboard RAM slots go bad—especially if you've had a power surge or have been rough with upgrades.
Here's how to isolate a bad slot:
- Take out all RAM except one stick. Put it in the first slot (call it Slot 1).
- Run MemTest86. If it passes, that stick and that slot are good.
- Move that same stick to Slot 2, run the test again. Repeat for every slot.
- If one slot consistently fails, it's the motherboard slot.
If you only have one slot, and it fails, then swap the RAM stick to a known-good system or try a different stick in your PC. If both sticks fail in the same slot, the slot is toast.
I had a client with a Dell OptiPlex that would crash under load. The RAM tested fine in another machine, but one slot on the motherboard was dead. We just moved the stick to the other slot and it ran for years.
What if you find a bad slot?
If you've got a spare slot, just move the RAM and carry on. If it's a laptop or mini PC with no spare slots, you're looking at a motherboard replacement. That's usually not worth it unless the machine is under warranty.
What if everything passes?
Then the problem might not be RAM or motherboard at all. Could be a failing power supply, overheating CPU, or even a driver issue. But 80% of random freezes and BSODs I see come down to memory or its connection to the board.
Your PC is only as stable as its weakest connection. RAM is the first place to look because it's so easy to test.
Final Thoughts
Don't overthink this. Reseat first—it's free and takes seconds. Then let MemTest86 do its thing. If it points to a slot, you know the fix. The key is to stop guessing and start testing. Now go fix that machine.