The Bad Pool Caller is a computer error which can appear on Windows based computers. It manifests in form of a so called “Blue Screen”, usually right after the computer is started, at boot time. A blue computer screen might flash with a message about “Bad_Pool_Caller” and some cryptic number.
The computer might reboot again shortly thereafter, finding itself in an endless loop of blue screens and failed attempts to start properly.
The pool caller error typically appears after new hardware is added, but it can also appear after certain software has been installed or after certain updates. Another common scenario for the error would be that the error appears right after Windows update has been run, while the computer worked properly before the update.
What makes this PC error so tricky is the fact that it can be caused by faulty hardware but also by faulty software, for example a faulty driver which just has been installed or updated.
The bad pool caller error could come from a defective memory chip, or from a driver incompatibility with your hardware.
How to fix it?
You should make sure that your hardware is OK by running a memory check. You can run the built-in memory test in Vista by pressing the F8 key when the computer starts to bring up the Windows Boot Manager.
Now go down to tools and select Windows Memory Diagnostic. The memory test will be performed. You can also press F1 and change it to advanced mode. Let it run and check the memory.
You can also try to remove hardware from your computer, unplug as much as you can and see whether the problem exists. Try to start your PC with the bare minimum on add-on cards in your computer. Then add more cards to your PC, one after the other, and observe whether and when the pool caller error appears.
If you do not have a problem booting on a CD/DVD like your Windows DVD, and if you did a memory test, then you know its not your PC hardware, but some software or driver problem.
To check your drivers and registry for Windows errors and to check for a damaged registry it is advised to use a tool called registry cleaner. A registry cleaner can repair and fix various computer errors, and it can help finding the cause for the pool caller error.