If their is anything I try to avoid, it is re-installing the operating 
system.
This might help, but you need your origional windows setup CD, or a copy of 
it on your hard drive.
From the run line, type
"sfc /scannow"  This will run a utility that will look for damaged or broken 
windows files.  When one is found, you will be asked to insert your windows 
CD.  The bad file will then be copied to your hard drive.
For some nasty microsoft reason, you need your CD, no other will work, even 
if it is the same edition of the windows operating system.  You have other 
SFC options, like "sfc /bootonce" that will scan all windows files on the 
next reboot.  You can try that if you can get the first choice to work.  you 
won't have windows or therefore speech until the process is done.  So try 
the first one so you know you have the right disk and it works.