Hello, my chm files cannot be opened. I get an error saying
"cannot open the file: mk:@MSITStore:C:\Program Files\Ahead\Nero\NeroExpress_eng.chm"
and
"cannot open the file: mk:@MSITStore:C:\Program Files\Registry Mechanic\Help.chm"

So what ever file i try to open it gives me the same error message, but the file path is different as its the file path of the file trying to be opened.
I have windowsXP Home edition SP2.
If there is enything else you will need to know, just ask.

'View - Folder Options' menu in Explorer. On the 'File Types' tab check that there is an entry for 'Compiled HTML help file' -if not, add an entry.

In open, specify "c:\windows\hh.exe" %1

Workaround:
hh.exe <chm file name>

i tried them both and still the same error message.

Did you consider simply re-installing XP over the top again...in repair installation mode? It would seem that you are either missing some key files or the links to those files in Windows are broken...a re-install should fix it