I have a windows xp {sp3} whenever I try to shut the pc
I am getting a message that
" its now safe to turn off the computer" and it get hangs.
any idea how to solve this ?
It HAS shut down - your computer isn’t powering off.
Scroll down to “Its now safe…” on this link.
Troubleshooting Windows XP Shutdown Issues
use ctrl + alt + del and u will find turn off quick fast it automatic kill task faster 
try this. real good Karen’s Show Stopper
[B]U r using non automated SMPS on old cabinet.
thats why this msg come.
actually ur comp is fully shut downed when it shows this msg.
change ur SMPS.
Buy new one.[/B]
+1 
older SMPS wil give you this message instead of doing a proper shutdown. Legacy of Win 95/98 times.