Helping my colleague- Mohammed on the issue where intermittently some of the asp pages start failing with Page Cannot be Displayed error.

Started  looking through httperr for connection_refused error to see if its related to  Non page Pool memory depletion but did not find any entry in there. Next thought was to check what was special with those pages . Nothing fancy surprises there . Couple of include files and bunch of response.write lines :)

Out of curiosity looking at c:/boot.ini. I see /3gb switch enabled. It was part of OS build done by customer.

With my experience I have seen atleast 10 different application issue with enabling /3GB switch

Refer KB Article:  http://support.microsoft.com/kb/316739

Note: Using only the /3GB switch allocates 1 GB to the kernel and 3 GB to the User-mode space.

Using this switch reduces the memory available in the following system pools:
•    Nonpaged Pool
•    Paged Pool
•    System Page Table Entries (PTEs)

If the specific server doesn’t receive the required amount of memory due to reduction in the kernel space because of enabling the 3 GB switch, the server or the applications may generate an error or stop responding.

Above failure was a side of effect of enabling /3gb switch in boot.ini file.

Removing this resolved the problem.