I had a client insist we complete a CHKDSK on a 125g laptop hd once. It took 197 hours. Hundreds of bad sectors. I'm guessing from physical damage. It can take a veeeeery long time. Yours is 500g.
If your hd only had a dirty bit and no physical damage, the scan would have completed in under 24 hours.
I suggested the diagnostic to get you an answer without waiting 7-10 days. Run the quick test. If the disk is seriously failing, that will find it.
You should be able to access the hd from its' bottom compartment to see the brand name. If it's Toshiba, it is rebranded (they don't make hd's). Run the Seagate DOS bootup diagnostic.