I found a hotfix in microsoft web site. "http://support.microsoft.com/kb/2265716/en-us"
is this ok for me?
According to this document -
This issue occurs because of heavy group policy use and the presence of SCOM causing a deadlock condition between the Lsass.exe process, the Redirected Drive Buffering Subsystem (Rdbss.sys) driver, and the Winsock kernel.
Does that apply to you? Are you (as listed in Symptoms of document)
A computer that is running Windows Server 2008 R2 or Windows 7 with System Center Operations Manager (SCOM) and a large number of GPOs (Group Policies) running a service that calls for Local Security Authority
If these descriptions fit you, then by all means use the hotfix but, if they do not, use it at your own risk.
How much memory are you using and what is the Maximum Ram you're allotted?
Try uninstalling a memory module and see if system hangs with less memory.
Edit: In addition, scroll down to JoselBarra's post on this thread.
http://answers.microsoft.com/en-us/windows/forum/windows_xp-system/pc-keep-getting-bsod-d1-7f-8e-and-freezing-caused/c26f1d00-12be-489e-84fa-f93db00d5668?page=3&tm=1325284937923