Remapping keys without external software

The best tool for the job is Microsoft's own remapkey.exe, available as part of the Windows Resource Kit. (That link is for Windows 2003; I've used it successfully over the years on many versions of Windows, including Windows 7; have not tested Windows 8).

remapkey.exe will write the mapping directly into the registry, I believe, and does not require a running process. You simply drag from actual key to desired key, and save.