How do I suppress "low memory" warnings in Vista Home Premium when running without paging file?

Open the registry editor (click the Windows orb, type “regedit”, and hit Enter).

Browse to

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\WDI\DiagnosticModules\

Export the following folders. This is your backup in case something goes wrong.

  {5EE64AFB-398D-4edb-AF71-3B830219ABF7}

  {45DE1EA9-10BC-4f96-9B21-4B6B83DBF476}

  {C0F51D84-11B9-4e74-B083-99F11BA2DB0A}

Take ownership of the each folder mentioned in step 3. (You can take ownership by right clicking the folder and then hitting permissions. Click the Advanced button and change owner to your user. Click OK and then give full control to your user group. Hit OK again.)

Delete the folders from step 3.

Reboot and enjoy.

Warning: After doing the above steps, you should know that once memory runs out, it is out. You will have no warning. Once your memory gets maxed out, programs will behave very erratic and suddenly crash without warning. I’ve decided that this side effect can be just as annoying as the popups. If you consistently push your machine’s memory to its limits, you should think twice about disabling the low memory messages.

Source

Of course you can always restore the 3 folders from the backup and Windows Vista will happily warn you again :)

PS: This works for Windows 7 as well.