My old hard drive w/ partitions was removed from my desktop PC and I am using an external usb case, but windows doesnt recognize it because its a 'dynamic disk'. I have tried a couple of programs to convert to basic disk without losing data but they havent worked. Any ideas?
Check if your PC has raid array turned on.
It could be that your PC bios is set to raid instead AHCI.
If it is set into raid mode, put your drive back inside the pc and recover your data with some good tool as GetDataBackPro, save those on a second hard drive.
After that, return into the bios and set it to AHCI, then you can reinitialize the 'dynamic disk' into basic disk.