This may not be your problem.
When you install mint and it gets to the partitioning page, make sure you are installing it to the hard disc rather than the USB stick (or dvd drive).
Sometimes the default option is not what you want.
Another problem that can arise is with the default settings for Grub (Grub2 for newer versions) - check that Grub is being installed to the correct drive.
It helps if the hard disc is partitioned as ext4.
In the BIOS make sure your hard discs are ACHI (or something like that). XP doesn't like ACHI if I remember.
If for any reason that setting has changed mint may not boot.
I have never previously heard of a linux system being corrupted by a software install but someone will probably come along and tell me I am wrong.
Having reread your post.
When you reinstall and get to the bit where it talks about partitioning, delete all the partitions and reformat as one ext4 partition.
Refresh (or something similar) and then make sure your installation is to the correct disc.
It may help to install with only the target disc in the machine - just remove the data cable to the other hard discs for the time being.
Which version of mint are you trying to install?