Sony vaio laptop reboots over and over again...

Found this that worked for some:

The possible reason for this is the newest Critical Patches, please
uninstall KB893066, KB890923, KB890859 and KB893086 following directions below:

You might have to print this...........

Please follow the procedure suggested by microsoft to solve BSOD
problem from the latest windows update.

1. Insert the Windows XP startup disk in your floppy disk drive or
insert
the Windows XP CD in the CD drive or in the DVD drive, and then restart
your computer.

Note When you receive the following message, press a key to start your

computer from the Windows XP CD:
Press any key to boot from CD

Note Your computer must be configured to start from the CD drive or the
DVD drive.
For more information about how to configure your computer to start from
the CD drive or the DVD drive, see the documentation that came with your
computer or contact the computer manufacturer.

2. When you receive the Welcome to Setup message, press R to start the
Recovery Console.
Note Multiple options will appear on the screen.

3. Select the Windows XP installation in question.
Note You must select a number before you press ENTER, or the computer
will restart. Typically, only the 1:
C:\Windows selection is available.

4. If you are prompted to type an administrator password, do so. If you
do not know the administrator password, press ENTER. (Typically, the
password is blank.)

Note You will not be able to continue if you do not have the
administrator password.

5. At the command prompt, type cd $ntuninstallKB.........HERE THE
NUMBER OF THE PATCH.....$\spuninst, and then press ENTER.

Note After you complete this step, you cannot stop the removal
process.

6. At the command prompt, type batch spuninst.txt, and then press
ENTER.

7. After the Ptach is removed, type exit, and then press ENTER oo
Uninstall the Next

please uninstall
KB893066
KB890923
KB890859
KB893086




Otherwise:
http://support.microsoft.com/default.aspx?scid=kb;en-us;156669