On boot Windows XP freeze!!!!!!! That is to say on boot screen of WinXP the loading bar continues to move, but the HD don't load. In my opinion this happened when I use a tweak that gave more power to CPU:
rundll advapi32.dll,ProcessIdleTasks

There's a way to remove it and to return at the original situation?

Thanks and excuse me for not perfect English!

Have u tried safe mode?

That does not do anything that would wreck your computer (unless possibly you lose power during it), and it doesn't give more power to the CPU; think of it as a special defrag.

In order to be of more help we need to find out what actually caused this.

yeah safe mode and try to undo the Tweaks .... wanna know where u got this sh** ?
2. try last good know config in boot menu .....
3. try to wait ... I mean really wait put PC on at night and look what happened on morning ...

Try running a chkdsk /r from the recovery console,
Try safemode / last known good
Try loading a backup of your registry hives in the recovery console.

Or if all else fails, install windows overtop its self

Wonderfull!!!!!!! I resolve it!!!

I remove the follow tweak:
DisableNtfsLastAccessUpdate

I disable also the tweak for the fast shutdown, because also it give me the same problem. Thanks a lot!!!!!

.... LOL your computer got some strange problems .... LOL

both of the options simply CAN'T cause this ....

DisableNtfsLastAccessUpdate = is just a little date when the file was accessed last time...
fast shutdown = just a shorter time till a process is forced to close on shutdown

maybe you should think of reinstalling windows ....