Windows freezing

[SDH]

I have had problems on and off with my Sony running XP
just freezing and leaving me no choice but to reboot. Now
I've started getting a message on start-up "N-Case alert
removed". It asks if I want to reinstall. I say yes but
after that evrything is locked up. On one occasion even my
keyboard is nonresponsive. I've also tried not
reinstalling but same response. Also tried using "Go-Back"
to a point I didn't have this message but am still getting
it. This message may just be a symptom of the problem(?).
Any ideas?

 

[Rich Barry]

http://www.symantec.com/avcenter/venc/data/adware.ncase.html