Well from the Winxp cd, its an option after it boots to go to the recovery console.
I find running it from there is more comprehnsive then using the one that reboots the lappy from windows.
The defrag in windows is made by Executive Software, who make Diskeeper (which for the record, was the 1st nt defragger, M$ used to say it wasnt needed, silly them)
Get yourself a FULL version of diskeeper 7 (hehe ok, its diskeeper 8 now) http://consumer.execsoft.com/home.asp?RId=50
Then go to the set it and forget on the boot drive by right clicking on the drive.
Then select boot time defrag, and select all all the options, INCLUDING run chkdsk, you dont want to defrag a disk that is messed up.
If you dont have a lotta free space, this will take hours, so be prepared, however you can pause the boot time defrag by pressing escape, and then waiting for the files that are being moved, to complete the process (dont shut it off)
Let me know if you need more info