Can you start in Safe Mode?
If yes try a System Restore to either a point prior to the change & or a point prior to this problem.
If you can't restore can you enter safe mode proper?
When did this all start? Chkdsk running/ freezing? Any idea what triggered it?
Also what is the make & model of the computer? What type of recovery disks do you have?
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Re: your second post: are you able to enter XP?
When you said chkdsk was freezing I was under the impression that you could not boot into windows?