trojan delf-658

Hi,
In my windows xp system,
pretty much all of a sudden,
names of certain folders have
changed in an alarming way.
C:\Program Files
has changed to
C:\Program Files.exe

similary for C:\Downloads
and C:\Documents and Settings

any new folder that I create in C:\
has this .exe extension.

I ran a scan with Claimwin antivirus and it
reported the above mentioned folders to
be infected with trojan delf-658.
But that is where it stops.

Then I got hold of Norton antivirus and it finds everything to be perfectly alright.

I restarted my PC but to no avail.
What to do?