Illegal Operation

[John Doe]

When I try to start my computer (compaq) w/ windows 98. I get a message that says.
Explorer  
This program has performed and illegal operation and will be shut down.  
I click close and no icons are on the computer.  
Someone HELP PLEASE.

Thanks  

[merlin_2]

boot to safe mode <ctrl or f8 key> and chose msdos prompt...a:\ the type cd enter   c:\then type scanreg/restore after the c:\ prompt.....maybe better still look here>http://www.windowsreinstall.com/install/oem/Compaq/Compaq_98quick.htm