New SSD with new win 8.1, need help for other drives

I had an HP 240GB SSD failing with Windows 7 loaded. bought a new Samsung 250GB SSD and loaded a new Windows 8.1 OS. i have 3 other drives, 1 drive a 500GB HDD was reconized and being used now. but 2 3TB HDD that are seen in Disk manager, but listed as Foreign drives, no partitions and no unallocatable areas. these drives have data on them and was used in the last Windows 7 OS. Had used a Disk unlocker from ASUS with the motherboard to fix this, but is unsupportable in Win 8.1. any way to "unlock" the drives and use the data on the disks with out wiping them clean?

did you try to assign them a letter

It see the drive as a dynamic drive and will no let me assign a drive letter to it

Drives larger than 2TB require the GPT allocated I believe. Windows 7 did not have GPT support but Windows 8 does.

You can convert MBR to GPT but you will need Aomei Partition Assistant to do it without data loss. See here:

Learn to Convert MBR Hard Disk to GPT without Data Loss through Powerful Software

Scroll down to: AOMEI Partition Assistant: A Magic Conversion Tool, skip the first part.
Download from here rather than cnet.com: Download Aomei Partition Assistant - MajorGeeks
cnet.com often has additional junk embedded in their downloads so avoid it at all costs.

thanks will look in to this.