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I've installed 4GB memory module, got more than 1 GB free RAM, however XP can't open window anymore.

I knew there was a setting, we can increase a limit like thing, so I can open new things again. I right click the mouse, there is no sense at the moment, I need to close a few things before.

Can anyone remember that setting?

OS: Windows XP Pro 32bit

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What do you mean it can't open a window anymore? Does this problem happen immediately after a reboot? – Mehrdad Apr 20 '11 at 7:03
You click something and nothing happens. Windows can't use more resources until you release something... No new window, no popup menu, nothing... I run many apps. at same time. Windows has enough free memory + swap space. I need to set something but I couldnt remember. – Nime Cloud Apr 20 '11 at 10:22

There is a hard window limit for Windows XP, it's apparently 50-60, I don't entirely believe that. It will reset when you restart, so if it isn't cured by a restart you're definitely heavily infected.

To cure this, run less programs. If you use Internet Explorer upgrade or change browser. You probably need to clean and trim down Windows. How many processes do you have open, it tells you in Task Manager.

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I don't know the count but I open Photoshop, Visual Studio, tons of Chrome, a few Explorer windows... I knew there was a tweak... – Nime Cloud Apr 20 '11 at 11:59
Search registry for Windows SharedSection=1024,3072,512 and increase the value 3072. I will post the complete answer when 24 hours limit done. – Nime Cloud Apr 20 '11 at 12:21
up vote 0 down vote accepted

Yeah I found it at the end: Desktop Heap

There is a form of limit in Windows that affects the NT family of systems - usually referred to as the "desktop heap". Hitting the limit is manifested as either a DLL initilization error for USER32.dll or an out of memory error. Fortunately, the limit it tweakable (after NT 4 Service Pack 2 at least), but the default settings are low enough that the limit is easily hit. Blockquote

Blockquote To tweak the limit, take a look in the registry at HLKM/System/CurrentControlSet/Control/Session Manager/SubSystems - there is a key called "Windows" that contains (among other things) "SharedSection=1024,3072". Changing the SharedSection entry to "1024,3072,512" increases the size of the "hidden" desktop heap. If that doesn't work, try increasing the second of the comma delimited values (e.g. 3072 -> 4096), which is the size limit of any particular desktop heap.

I'm not sure if this is the limit the poster of this Ask Slashdot is hitting, but I do know that we have problems with this particular limit at work. We run an interpreted language/database/remote development environment, including customer applications as Windows Services. After stopping and starting the service multiple times, we get a USER32.DLL error for one or more of the executables running under that service - the only resolution is to reboot the machine, even after applying the aforementioned registry tweaks.

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