Booting from the CD to fix the problem

First you need to make sure you have set and know the Administrator password.
If you know the password then skip this section.

There are menu ways of doing this... but I like sureshot methods.
press WINDOWS + R
type compmgmt.msc <press enter>
navigate through the left menu: Local Users and Groups >> Users
In the right panel, Right click on Administrator and choose Set Password...
You may get a warning about losing vital information, mainly you will lose any saved passwords for web sites, file shares. Usually not a problem unless you are constantly logging in as Administrator.
Continue passed this if you are still comfortable.
Set the password.

REBOOT off the XP CD
At the menu, choose to repair using the recovery console
(NOT AUTORECOVERY which shows during the loading phase of CD Boot)

At the DOS window prompt
type chkdsk /p
Let it do it's thing....
if you have multiple partitions, type D: <press ENTER>
then chkdsk /p again

Not sure what partiion your on? type DIR to find out.