computer wont shut down.

yes hello to all i have a question as per title my computer refuses to shut down the only changes that i have done is put in the xeon x5460cpu so idk if this could have something to do with it or not i mean i will shut it down and it will go through the process of shutting down u know it will say logging off and then say shutting down and then my screen will go black but all the lights will stay on along with my cpu fan will continue to run the only way that it will shut the lights off and my fans is if i do a hard power off u know hold down the power button, it will do the same thing if i tell my computer to go into hibernation too but heres the thing after doing the hard power off, whenever i power my rig back on it will go though everything normal u know, if i shut it down it will boot properly into windows without showing the one screen telling me that windows did not shut down properly or if i put my rig into hibernation after the hard power off it will go through the restoration process properly,so idk or could it be my new psu idk which on of these2 it could be but i suspect it to be my new cpu, any help will be great.
THANKS
RUBEN

Disconnect all nonessential USB devices and see if this helps. If it does, then there is a problem with a USB driver or a bios issue.

Also, do you have the latest bios installed for your motherboard and do you have the latest chipset and USB drives installed? Check motherboard mfg.'s website for updates.

yes i have disconnected all usb devices except my wireless keyboard and mouse and yes i have all updated and up to date drivers chipsets and bios. now i have been thinking right and could it be the cpu because it is originally a 771 socket but i retrofitted my mobo to take this cpu even though i have a 775 socket because i never had this problem with my rig before i installed the cpu and psu.
thanks
Ruben

Well, the retrofit being the issue question is certainly a valid one. If you force the power down by holding in the power button it may not hurt anything though. Sounds like it doesn't lock up until you are already out of windows and any changes have been saved. Does it lock up like this when you try a restart or only when you try to turn it off from Windows?

only when i try to shutdown
THANKS
RUBEN

I know it's an annoyance. We all like for our stuff to work perfectly. But on the other hand I'm betting that's all it is: an annoyance and isn't hurting anything. One last idea: Set the Windows power scheme to High Performance and also disable all the stuff in bios that has to do with sleep and hibernation.

yes hello i did try that which was the high performance thing and im not sure what/ if there is anything in the bios that has to do with sleep and or hibernation, the only thing that i can think of in the bios is the the cpu configuration which is the speed step technology and the c1e state. please advise if u think this will repair my problem thanks for all of your help.
THANKS AGAIN
RUBEN