how can i extract my files from a bad hard disk partition.

hello,i had pr
oblems with my computer so i had to reinstall my windows OS on one of the two partitions on my hard disk. i tried opening the second partition after the installation to copy some file but it was complaining that the drive is not formatted. is there anyway i can correct this or how can i get out my files before formating the drive. is there any software that can help is this case.

You can try to boot the machine with any number of boot discs including Linux or Unix discs. Then mount the partition.
OR
Take the drive out, put it in an external USB HD enclosure and connect it to another PC.

Or put it in a different computer internally.

How would that help? The idea is to try to read the drive without it booting. That's the reason for the boot disc or the USB enclisure.

I don't mean boot from it. Boot from the other machine's drive and just keep it in there as a second.

Putting it in a different machine would achieve the same goal for reading files from it, without having to purchase an external enclosure. Also would be faster transfer-wise.