Is there an upate to Apple Hardware Test? It locks up while testing
There have been many updates…
unfortunately your machine is too old to use them.

It can only use a DVD-based version, not the latest internet-based test.

There is a blog post about how to boot to AHT from a downloaded AHT file, loaded to a USB key, but you will need a working Mac to be able to construct it.

From : Riven by Five - Download and run Apple Hardware Test (AHT) from a USB drive.

My additions in italics


  1) Download the AHT for your computer (see downloads below for specific models).
  
  1b) My copy had me convert the downloaded .dmg from some “old” type using Disk Utility. (Just open the .dmg in Disk Utility and “Convert” to a new target, then mount the target.)
  
  2) Mount and completely wipe a USB stick.
  Format it GUID/Mac OS Extended (Journaled)
  Most USB sticks will be MBR/FAT by default, so just formatting to Mac OS without changing the underlying structure to GUID will not work
  
  3) From the AHT image, copy /System to the root folder of your USB stick:
  by typing the following in Terminal [Applications/Utilities]
  
  cd /Volumes/USB_STICK/ &amp;&amp; cp -r ~/AHT_ARCHIVE/System 
  
  4) Now, from the USB drive, copy the /System/Library/CoreServices/.diagnostics/diags.efi to the root directory:
  
  cd /Volumes/USB_STICK/ &amp;&amp; cp ./System/Library/CoreServices/.diagnostics/diags.efi
  
  5) Shutdown all applications, except Terminal.
  
  6) the original 6) below assumes you are booting to the same machine you are trying to test
  to attempt to use this on a different machine omit the &amp;&amp; sudo reboot &amp; instead eject the USB after that command, then move to your target machine  
  
  6) “bless” the USB drive in mount-mode, with the EFI file, and immediately reboot:
  
  cd /Volumes/USB_STICK/ &amp;&amp; sudo bless --mount /Volumes/USB_STICK --setBoot --file diags.efi &amp;&amp; sudo reboot
  
  7) Cold boot your target machine
   You should now be booting into AHT -- don’t hold down any keys. 
  
  8) Run the tests, and yank the USB key after AHT reboots you.
  
  You can download the AHT package for your computer using this URL: 
  
  http://download.info.apple.com/Apple_Hardware_Test/018-[MODEL NUMBER]-A.dmg 
  
  where [MODEL NUMBER] is the four-number ID below:
  
  3282 for Mac-F4208AC8, Mac-F42289C8 Xserve1,1 and Xserve2,1
  3259 for Mac-F42C8CC8 MacBookAir1,1
  3273 for Mac-F42C88C8 MacPro3,1
  3254 for F4238CC8, F42386C8, F4218EC8, F4208EAA, F4208DC8, F4208DA9, F4238BC8, F42388C8 and F22788C8 inclusively.  
  
  or more specifically:
  3085 for Mac-F22788C8 MacBook3,1
  2886 for Mac-F4208EAA Macmini2,1
  2845 for Mac-F42386C8 iMac7,1
  2833 for Mac-F42388C8 MacBookPro3,1
  2770 for Mac-F4238BC8 MacBookPro3,1
  2769 for Mac-F4208DC8 MacPro1,1
  2667 for Mac-F4208DA9 MacPro2,1
  2766 for Mac-F4208CAA MacBook2,1
  2592 for Mac-F42189C8 MacBookPro2,1
  2591 for Mac-F42187C8 MacBookPro2,2
  2590 for Mac-F4208CA9 MacBook2,1
  2579 for Mac-F4218FC8 iMac6,1
  2535 for Mac-F4218EC8 iMac5,2
  2534 for Mac-F4228EC8 iMac5,1
  2533 for Mac-F42786A9 iMac5,1
  And these are there, but too old to identify: 2418, 2405, 2398, 2393, 2392, 2342, 2216, 2215, 2158, 2120, 2079, 2056, 1880, 1879, 1680 and 1594.