An external hard drive won't open because it is not accessible some how. Will you guys be able to fix it without formatting it?

Opening up the enclosure can be quite a challenge on some of these external drives, as a result it may end up costing quite a bit. The good news is that it rarely happens. Also formatting may need to be done, but bring it in and ask them first. Hopefully all goes well!

Micro soft would be the best place to go

There's a couple ways to do it, before formatting it . They might have better solution good luck

The may be able to do it but it'll cost a lot of $$$$$ if 5hey need to open it.

It depends what these guys need to do. It varies alot... They might need to open the enclosure on the drive itself to make sure the connection is good too