When you install Windows XP SP1, you receive:
The <path>\Update.inf file is not correct.
If Cyptographic Services has NOT been started, you will receive this error.
To resolve this problem:
1. Open a CMD prompt.
2. Type net start "Cyptographic Services".
3. Install Windows XP SP1.
NOTE: See the fix from tip 6448 » 'Service Pack 1 Setup could not verify the integrity of the file'?