An error has occured in InternetExplorer

I am facing a problem in network client win2000 pro pc. I got an error

a) An error has occured in internet explorer. Internet explorer will now close. If u continue to experience problems, please restart your computer.
The same pc shows another error

b) The exception Illegal Instruction. An attempt was made to execute an illegal instruction( 0xc000001d) occured in the application at location 0x63590940. Click on Ok terminate the program.

please help me..

regards
anzar