I am using vista home edition with 2G ram. From time to time after I work with my laptop for a period of time, I can not open any of programs, even my computer. Damn, is it really my computer?  QQ throws me a out of memory message window, Sometime a new window is opened with the frame only, no button, no menu... weird. Actually, the time period is not fixed. I thought it was relevant to how many application I was running.  I have to perform a manual reboot to release "memory", although the system indicated system memory only consumed about 70%. I spent a long time to find solution and installed all latest system patches,but not help at all.

Here is a solution I found today. I am not sure whether heap size is the reason, and need time to testify.  But it sounds reasonable to explain my situation. I hope it is, at least I can have chance to solve the terrible issue.  The default heap size is set to 3072. Fortunately heap size can be adjusted, but in registry.

The following solution is offered at http://forum.notebookreview.com/showthread.php?t=177272

All registry edits bring a dose of warning and danger. Please be careful and read the following instructions:
1. Click on Start - and in search type regedit and press enter.
2. Go to HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control\Session Manager\SubSystems\
3. Make backup of your key! Click on File menu and choose Export. Give it a name and choose the destination. Click Save and there it is - a backup of your SubSystems reg key. Just in case you want the original key back.
4. Doubleclick on Windows key in the right pane.
5. In Value data field scroll left or right using arrow keys until you find this:
SharedSection=1024,3072,512. Change 3072 into 4096 so it reads: SharedSection=1024,4096,512
That is it! Now you can open more tabs, windows, start more processes and enjoy less restarts and shutdowns and more sleeps and hibernations. Good trick for notebooks!