Hi Real_Luzu
Please explain, why you need to change your HWID, is that for hacking games?
In all honesty it is a really bad thing to do to change your HWID, most of the software on your PC, including Windows may kick out and will refuse to activate if you change your HWID
If you do want to go ahead and do that:
Click your Start Button, type regedit and hit Enter to open the Registry Editor
Click View and make sure 'Address Bar' is turned on
Paste this into the Address Bar at the top and hit Enter
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\IDConfigDB\Hardware Profiles\0001
The key you are looking is on the right hand side - HWProfileGuid