Hi Mel,
In Safe Mode Just a limited or essential MS Platform Programs will RUN, The
OS will Run The basic Drivers and Programs for Booting up, so if you have a
Spyware/Virus Runing a Processes on your Machine it will not run in Safe Mode
( that May be or the sets of command available for it is limited you can say).
In Normal Mode is the Opposite, all Processes Wake up and Run on the OS.
For that reason most websites say Run the Scan first in Safe Mode, but also
you Need to run in Normal Mode to get the whole benefit of getting Rid Of
Spyware/Viruses on your System.
Hope this helps
Regards
nass