My son encrypted pc and does NOT rember password and to top it off the PC must have a loose wire because every time you turn it on and then move it the PC turns off.PLEASE HELP

Encrypted with what software? Make sure the power cords (internal/external) are all seated?

Encrypted the data, password protected the computer at bootup, password protected the user login...?

If data are encrypted, you may be out of luck.
If computer is password protected at bootup it means he got probably got into the BIOS and set a password. Most systems have a jumper on the main board you can set to kill the password in the BIOS. You didn't mention if it's a laptop or desktop but I found this at Dell's site on the desktop.
http://support.dell.com/support/edocs/systems/dim5150/en/sm/syssetup.htm#wp1100963

If the user account is password protected, depending on exactly what version of your operating system is (XP Home, XP Pro, Vista Home Basic, etc.) there are different ways to reset a user's password.

Too many possible scenarios here without more specific information.

http://en.wikipedia.org/wiki/TrueCrypt

My son used this software and encrypy the hard drive,it is a Dell 5150 laptop that was bought in 2005 and window's xp

He used truecrypt 5.1 turn on pc push escape and comes back with no bootable partition found

According to their web site at http://www.truecrypt.org/faq I forgot my password – is there any way to recover the files from my TrueCrypt volume?
TrueCrypt does not contain any mechanism or facility that would allow partial or complete recovery of your encrypted data without knowing the correct password or the key used to encrypt the data. The only way to recover your files is to try to "crack" the password or the key, but it could take thousands or millions of years depending on the length and quality of the password/keyfiles, on software/hardware efficiency, and other factors. :sad:

You might do a Google search on "cracking truecrypt password". Lots of replies but the few I read said it's a no-go.

TrueCrypt asks ,when your encrypting, to set the encryption key length.
The longer the key ,the less chance you have of cracking it.
He's going to need to remember it or you;ll end up doing a reformat & install of everything you had.
You could try booting with a Linux disk and see if anything shows up in the drive.

Found original Window disk ,reformatted the hard drive,now to find out why it shuts off if you move the PC, Can I disconnect the cd rom drive,The PC shut off when I open the door or move the cd holder

Yeah you can disconnect the CD but I'd just remove and reseat all the connections while it's turned off.
Same for the memory ,remove/reseat.
Any one could be a bad/loose connection.

And give your kid his own user name/password on a restricted account without admin rights.

any idea how to take apart THANK YOU

Didn't realize this is a laptop.
Here's the service manual (http://support.dell.com/support/edocs/systems/ins5100/en/sm/index.htm).