Windows turnoff computer keeps popping on while am surfing the net

[Guest]

anyone help me
while surfing the net i keep getting the turnoff computer box on my screen, if i click cancel it does not work until i click over 30 times and there after it closes all programs open and clears out the taskbar thus cuasing me to restart my computer. i have got mcafee fire wall running and virus scan which are regularly updated and scan for virus's trojans at starup all the time this is clear... what could be the problem i am running windows xp home ed...comp is 4 months old i have a feeling someone is hacking into my computer but firewall is running securely...any ideas

 

[Willie]

Check for Spyware;
Lavasoft Ad-Aware - www.lavasoftusa.com
SpyBot S&D - http://www.safer-networking.org/
CWShredder : http://www.spywareinfo.com/~merijn/files/CWShredder.exe
Online Spyware scan: http://aumha.org/a/noads.php
Stinger- http://vil.nai.com/vil/averttools.asp
Hijackthis: http://tomcoyote.com/hjt/
Also: http://www.net-integration.net/tools/hijackthis.html
SpywareBlaster: http://www.javacoolsoftware.com/spywareblaster.html

Willie

anyone help me
while surfing the net i keep getting the turnoff computer box on my

screen, if i click cancel it does not work until i click over 30 times and
there after it closes all programs open and clears out the taskbar thus
cuasing me to restart my computer. i have got mcafee fire wall running and
virus scan which are regularly updated and scan for virus's trojans at
starup all the time this is clear... what could be the problem i am running
windows xp home ed...comp is 4 months old i have a feeling someone is
hacking into my computer but firewall is running securely...any ideas