I came across this problem a few months ago, and forgot to write it donw. Today, another developer was having the issue, so I decided to write it up here.
For some reason, when opening Performance Monitor and attempting to add performance counters, no counters are available. There is a KB article from MS that gives a solution to the problem:
http://support.microsoft.com/default.aspx?scid=kb;en-us;Q248993
Essentially, you need to set a registry key called Disable Performance Counters to 0. There may be more than 1 of them, so search from the HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services to find them all.
Hope that helps someone