Extremely slow pc

my pc is running extremely slowly after i installed a 40GB sata hd.it takes 20-25 min just to boot but mostly its just stuck on check disk screen @ 0% and whenever on a rare ocassion it does boot up properly it takes ages just to open firefox....is this a bad sector hd problem? Never had such experiance with me previous hd which unfortunately stoped functioning

your PC specs?

Is that HDD new or used?


Also please specify which power supply are you using