when trying to boot PC get error message explorer caused an invalid page faullt.

I have a windows 98SE machine,i went away for lunch and came back and it had crashed so I rebooted.
I have tried to boot my machine and everytime I get the following message.
EXPLORER caused an invalid page fault in module EXPLORER.exe at 0167:00401f31. and then the screen just sits there with no icons or task bar and i cannot get into windows not even in safe mode.
I have tried to re-install WIndow 98 and keep getting error message
An error occured loading c:\windows\system shdocvw.dll the file may not have been installed or it is corrupt
aslo An error occured loading c:\windows\system\shdco401.dll the file may not have been installed or it is corrupt
and then to top it all unable to install Java packages from c:\windows\java\classes\xmlds04.cab calss not registered
and unable to install Java packages from c:\windows\dajava.cab class not registered
I have tried all suggestions on experts-exchange relating to this problem but still no joy
I have done loads of reinstall of windows 98 SE without any problems but this one has me beat.
In this instance I do not want toformay as I have a lot of data on this machine that I need to keep.

HELP

Ramz8