First

lease confirm the spelling "syshost.exe".
If you are absolutely certain of the spelling,and it is
precisely as you have typed it,boot into safe mode and
try to delete it,as "syshost.exe" is NOT a legitimate XP
file.
The true XP file is named svchost.exe. It is a legitimate
programme,which is not malicious, found in the System32
directory.DO NOT DELETE svchost.exe from system 32.
I will run a search at the virus library for specific
removal instructions for W32.Francette.Worm.It is
extremely rare.
Sadie