For the last several days, I have utterly failed to use my computer for any purpose at all, be it internet, or Office 2007, because I just can't start my operating system.
As soon as I switch on my computer, and try to log on by writing my password, I get the following message:


SVCHOST.EXE Application Error

The instruction at “0x7c910cae” referenced memory at "0x00000000". The memory could not be read. Click on OK to terminate the program, click on Cancel to debug the program.


I am at my wits' end as to how to surmount this problem.
ANY HELP please?

A repair installation should be able to fix this - you would need an installation disk

Repair Installation
A Repair Install will replace the system files with the files on the XP CD used for the Repair Install. It will leave your applications and settings intact, but Windows updates will need to be reapplied.

A Repair Install will replace files altered by adware and malware, but will not fix an adware, malware problem.
Perform a Repair Installation (http://www.microsoft.com/windowsxp/using/helpandsupport/learnmore/tips/doug92.mspx)