Try running Check Disk:

start Run... cmd

Type:

chkdsk /f

When asked if you want to run on next boot? Y or N?

Type: Y

And reboot,

This will check for and fix any hard disk errors.


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As to your slowness:

As a first response you might want to post a HijackThis log for review by our Pros in that section:

Please follow the instructions HERE & then post your log in a new thread in the Spyware, Adware, Viruses and HijackThis Logs section.

(Not in this section please).

Please specify what issues you appear to be experiencing along with your log.

Also as one of our staff is currently off-line please be patient.