can you get into the Recovery Consiole?
If so run chkdsk /r (note the space because without it you will likely get the error message you indicated)
This link explains how to access and make use of the Recovery Console:
If you do not have an installation disk that allows access to the Recovery Console and do not have a floppy drive for creating the set of XP installation Floppies available here - http://support.microsoft.com/kb/310994 - (be sure you get the correct version and service pack for the version and service pack you currently have installed) you can follow this link to download NTFS4DOS (free for non-commercial use) http://www.free-av.com/antivirclassic/avira_ntfs4dos.html
When you create the boot floppy (which can then be used to create a bootable CD) you can choose to integrate checkdisk and defrag tools. This Adobe Acrobat file explains it in detail.
Before doing that though did you try running chkdsk /R from Safe Mode?
Using 4 year old HP Pavilion/XP/sp2. Check disk cannot finish due to unspecified error. Reschedule to run again on startup same thing. Defrag won't run because chkdsk/f needs to be run. Went to Run (per MS) entered chkdsk/f and it says not found. Error Checking scans files then stops at 54% complete checking indexes. Computer newbie and first time in a forum. Appreciate help!