Weird hard drive problem

A system restore would reverse the installing of the printer drivers and the updates. Since you had a power outage, my first guess would be that the drive is damaged, but since you say the drive works on other PCs this seems highly unlikely.

You may have seen the partition table corrupted on the external unless you have full access to everything when plugged in on a second machine. That would explain why folders suddenly vanish.

You may want to try a different port if this is a usb model. Use the right click on the green safely remove usb device icon in the system tray first and unplug it from one port to move other to the next. The fresh detection may restore full access.

Another USB port didn't help.. Doing that and going to Disk Management shows something strange. Disk 0 is the primary, Disk 1 is the external, and a strange Disk 2 that is the exact same size as Disk 1 but labeled unallocated space. So It is reading the disk twice? I plugged it into my notebook and while I can access all of the files I still can't run chkdsk. It gives me a "can't open volume for direct access" message. I really would like to avoid reformatting and restoring 300 gigs!

Get going backing what you can up on the laptop. It strongly points at the MFT being toast and before losing your shirt get what you can off even little at a time.

The outage may not have damaged the drive itself but likely was what saw that trashed if cut off while you were accessing it or a program was. Something got stuffed!

Was the original factor partition or did you reformat it first before placing any files onto it? The first thing I plan on with any new drive(internal = raw, flash drives = factory Fat32) is reformat or even nuke the original volume off entirely! I can alway reformat back to Fat for Linux or some other application if needed but prefer NTFS from the start.

Once you get some data off onto the laptop you can transfer files over to the desktop if you have a flash drive or another drive available for safekeeping. But you may as well as plan on simply wiping the drive and repartitioning, reformatting it to insure a working volume is on rather then risk a sudden vanish of everything despite the efforts!