Try the following on the troublesome machine.
1.  Advanced windows care.  from iobit.  The later advanced system care 
doesn't work with speech.
2.  ccleaner.
3.  A good anti-virus program.
4.  spybot search and distroy.  All versions talk well.
5.  Malware bytes version 1.75.  The lates version doesn't talk, very 
disappointing.
If anybody needs them, I can put them in a zip file and make a dropbox link 
for download.
6.  Absolutely, switch from IE to Firefox on any XP machine.