When Windows 7 Service Pack 1 was released, a lot of people were complaining about the problems they were getting after installation. A lot of experts also advised to stay away from SP1 because it was creating problems for some people although most of the people were fine even after the installation of Service Pack 1.
Microsoft was investigating the issue for a long time and it turned out to be the problem with the Windows Memory Manager. When the computer starts using high memory due to a lot of programs open at a time, the memory manager starts requesting paging in and paging out request and ultimately the computer freezes. This problem is due to a system file called Microsoft Filesystem Filter Manager (fltmgr.sys).
Microsoft has released a hotfix for this problem. By installing the hotfix, you can easily get rid of the freezing problem. You should download and install the hotfix as soon as possible as it is high priority.
Please note that you will need to click on View and request hotfix downloads link at the top of the page in order to download the hotfix. This hotfix also applies to Microsoft Windows Server 2008 SP1.