|Freeze-ups can be a pain to find. They mean that the computer has lost its way and can often be due to some wrong file version somewhere.|
I would be inclined to replace Iphlpapi.dll using sfc because you shouldn't be getting error reports.
If you use IE, that can collect wrong file versions and is well integrated into Windows. Try running IE Repair and if it has problems note what file is reported. Copy the following into the Run box then run it offline:
Change 6 to 5 if you are still using IE5.
The above is one "Aspirin", another one that often helps is to Restart in MS-DOS and type scanreg /fix (which rebuilds your registry and is quite safe). Type exit to restart Windows. Hit Return key after all commands.