Hi there, with regard to sfc it is
sfc /scannow
Don't forget the space between sfc and the /
Make sure you have your Win CD in the drive.
With regard to help and support, here's a few links
Why doesn't Help and Support work?
http://www.kellys-korner-xp.com/top10faqs.htm
Troubleshooting Help and Support
http://www.kellys-korner-xp.com/xp_h.htm#h&s
Repairs Windows® XP Help and Support after running Easy Cleaner or similar
registry cleaners.
http://www.dougknox.com/xp/utils/fix_windows_xp_help.htm
Start Menu/Help and Support doesn't work:
Click Start then select Run and type in: helpctr -regserver
To reinstall Help and Support:
Locate the file called: pchealth.inf
This is located in C:\Windows\inf
Right click and choose install.
Make sure you have your WinXP CD ready.
Note: The folder is hidden by default.
Click Start, then select Run and type in: control folders.
Go to View: Show hidden files and folders and uncheck Hide extensions for known
file types.
Restore winhlp32.exe for XP or XPSP1 (Line 57)
http://www.kellys-korner-xp.com/xp_tweaks.htm