You need a blank CD-R or CD-RW and a CD-writer, or a blank USB or floppy disk to follow instructions in this article.
Please note that the USB method applies to USB thumb drives only, external hard disks are not supported.
If you have no CD-writer or USB boot support, but you do have a floppy disk drive, you can create a bootable floppy disk for memory testing.
Because the selected media will be formatted in the preparing process, make sure your CD-RW, USB flash disk or floppy does not contain anything important.
If you have your Windows locking up (hanging) or doing random reboots for no apparent reason, then the problem often lies in defective memory. If you have overclocked your computer's processor or set the memory timing manually, try reverting back to defaults - this might help more than you can imagine.
Do not ignore faulty memory modules, for this can easily lead to data loss - hard disk or SSD contents messed up or even deleted.
Open Memtest86+ home page.
To get the bootable CD image, click Download - Pre-Compiled Bootable ISO (.zip). Be sure to click on the link with "(.zip)" at the end, the other one cannot be opened by Windows Compressed Folders program.
To get the bootable USB thumb drive image, click Download - Auto-installer for USB key (Win 9x/2k/xp/7).
To get the bootable floppy image, click Download - Pre-Compiled package for Floppy (DOS - Win).
In File Download dialog, click Open.
After download is complete, Windows will open it with Compressed Folders program unless you have some other file compression program (such as 7-zip, WinZip, WinRAR) installed.
In Windows Vista and 7, click the Extract all files button on toolbar.
In Windows 8/8.1 and 10, click Extract all on Ribbon. If Ribbon is not visible, use keyboard shortcut Ctrl+F1 to reveal it.
In Windows XP, the Extract all files command is in Common Tasks Pane on the left. If you have disabled Common Tasks, use keyboard shortcut Ctrl+A to select all files and then select Extract command from File menu.
Windows Vista, 7, 8, 8.1 and 10 users should click Extract and all files will be extracted to a new sub-folder. The new folder will open automatically after this.
In Windows XP, extracting the compressed files includes many more steps.
First, Compressed (zipped) Folders Extraction Wizard appears with Welcome page. Click Next.
In the Select a Destination page, click Browse to select a better destination folder. By default, the not-so-wise wizard wants to extract all files into Temporary Internet Files folder.
Select a destination dialog opens. Click OK to extract the files into a new sub-folder in My Documents folder.
Back in the previous page, click Next.
Finally, click Finish. The new folder will open automatically after this.
For the downloaded CD image, Windows XP, Vista and 7 users should double-click the mt<version number>.iso file to open it with default disc burning program.
Windows 8/8.1 and 10 users should right-click the file and select Burn disc image from the menu - by default, Windows 8/8.1/10 mount disc images as new drives.
For the downloaded USB image, insert your USB thumb drive and double-click the Memtest86+ USB Installer.exe executable file to start the program.
For downloaded floppy image, double-click install.bat in folder named floppy.
After double-clicking the executable file, Windows checks for digital signature in the file. Because the file is not signed, Windows XP will pop up an Open File - Security warning dialog. Click Run. Windows Vista, 7, 8/8.1 and 10 users will see the most beloved User Account Control warning instead. Click Continue or Yes.
Memtest86+ USB Installer Setup opens with License Agreement. Click I Agree.
In the Choose USB drive location page, select your USB Flash Drive letter and tick the (Recommended) Check this box if you want to format drive box.
Only USB thumb drive letters are displayed here, no external or internal hard disks can be selected for security reasons.
Make really-really sure you have selected the correct drive letter and that you do not have anything important on the USB thumb drive. Then click Create.
The process will take a minute or two, just stand by. Click Next after the Memtest86+ bootable USB drive creation is complete.
Finally, click Finish.
First, insert a blank CD or CD-RW. Windows XP and Vista users can use a free CD/DVD writing program, such as CDBurnerXP.
Windows 7 and later include the Disc Image Burner program that you can use for burning ISO disc images to CD-s and DVD-s. Click to check the Verify disc after burning box.
If you inserted a CD-RW with some files already written on it, Windows Disc Image Burner will ask whether you want to erase the whole disc contents or not. Make sure you do not have anything important on the disc and click Yes.
The disc burning will start. As the image file is not big (around 2 megabytes), it will take only some minutes until the burning is complete. Disc Image Burner will notify you with "The disc image has been successfully burned to disc" message in Status box. The disc will be ejected after this. Click Close.
A black command prompt window will open with Memtest86+ description. There might be some line about invalid CON code pages or an absolutely strange line with messy characters, just ignore that.
After a few seconds, a line Enter target diskette drive: appears.
Press A on your keyboard (if your floppy drive letter is B, then press B key). Then press Enter key.
If you still haven't inserted your blank formatted floppy disk, insert it now. Then press Enter as told on the screen:
After a few seconds Memtest86+ installation is complete. Press any key (Enter, for example) to close the command prompt window.
Now close all open programs, leave the CD, USB drive or floppy disk inserted and restart your computer.
If you have correctly configured your computer BIOS/UEFI to boot from the CD, USB or floppy disk, Memtest86+ will start automatically after the restart.
If not, Windows will probably start again.
Memtest86+ offers Fail-Safe Mode for a few seconds before starting the memory test. If your PC has stopped responding or rebooted by itself during previous tests, press F1 key.
Normally, you do not need the Fail-Safe Mode.
Let Memtest86+ run for 15-20 minutes before checking any results. Although Memtest86+ will easily run for hours, the first 15-20 minutes will always confirm the state of your memory modules.
If a memory module is not working correctly, Memtest86+ might stop responding or reboot computer. Check that WallTime value is increasing every second and use Fail-Safe Mode the next time.
If after 15-20 minutes values in last two columns, Errors and ECC Errs are 0 or empty, the memory in your computer is fine. ECC Errs will be displayed only if your computer and memory module(s) support ECC (Error-Correcting Code).
If an error count is over 0, you must replace the defective memory module(s). As said before, defective memory will lead to unexpected errors, random reboots and data loss.
Here is a computer with good memory modules.
To exit Memtest86+, press Esc key on your keyboard. Your computer will reboot. Remove the CD, USB or floppy disk and let Windows start normally.
Because there are very many different memory module types (such as DDR, DDR2, DDR3, DDR4 etc) and they also have different working speeds, I recommend using free HWInfo or Speccy to determine which memory module(s) your computer needs and whether there are available memory slots. The point is that you cannot put just any memory module in your computer. A possible solution is in the manuals that came with your computer - supported memory types and speeds are listed there.
If you have overclocked your computer, try changing settings back to defaults first. Memory modules might not be able to run at higher speeds or voltages.
Then run Memtest86+ again.
If your computer is still under warranty, check the manuals that came with your computer to find out where to call or where to take your computer.
If you do not know much about computers and parts they consist of, I strongly recommend having memory modules replaced by a specialist. Otherwise you might end up with broken memory modules, electronic parts ruined by static electricity, unintentionally unplugged cables or some other malfunction.