Windows 7 Disk not recognized

[Landers]

I have a 700GB external disk drive that my Dell x64 used to recognize when I plugged it in. W7 will no longer recognize it. I can plug it into another like Dell W7 machine and it recognizes the disk. Does anyone know why this problem is happening and anything I can do to rectify it? (It may have somehow been caused by my plugging an old disk from another computer into my Dell to see if it could be recognized, which it never would.)

File system: NTSF
Label: N_Container on N drive
Size: 698.63
1st Sector: 2048
Last Sector: 146519199
Used space: 100%

Thanks

 

[nmsuk]

Is it seen in disk management at all?

 

[nmsuk]

winkey + R type diskmgmt.msc then enter

 

[Landers]

Yes, I find it in there. I don't want to do anything that might cause the loss of data though.
Is it missing a label?

 

[Landers]

Fixed it. I had a USB thumb drive do the same thing, my 2nd machine wouldn't recognize it in a file explorer, so I experimented with it. All it took to fix both the unrecognized USB thumb drive and the USB portable drive was to assign both a drive letter. They then both began to show up in Explorer and Unreal Commander. Thanks for pointing me to diskmgmt.msc. I have used it before, but I use it so rarely, I didn't think about it.