expand perfh009.dat and perfc009.dat

I want to install Exchange 5.5 on a Windows NT cluster, but cannot. I find
out that the reason is when install Exchange 5.5, some changes must happen
with files perfh009.dat and perfc009.dat (in %SystemRoot%/system32). But I
cannot do anything about these files (I have the administrator right)
because they are used by another program. How can I know which program is
using them ? Or what can I do so that I can change these files (rename, for
example).
Thank you so much.
Ha.

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