I can't view my pictures from my camera on my PC?

I connected my Nikon D5100 to a computer my dad built (so I can't tell ya what kind it is). This is the first time I've had this problem so i don't know what's up.

The computer reads the camera as connected, but once the thumbnails show up, they disappear almost immediately and turn into some screwy file name, and when clicked on, I get a notice saying "we can't open this file."

So what gives?

It could be that the photos were shot as RAW files. You can easily determine if this is the case by looking at the file type. You do this by right clicking on the image and choosing properties. If the file type is not JPEG but instead something else like NEF, then you will not be able to view the shots unless you have the right type of software. To view Nikon's proprietary NEF file system, you must open the image using the supplied Nikon software. Or, if you have Lightroom, you might be able to open them using that too.

Corrupted files.

There's a problem with the memory card. It's either failing or it was handled improperly (mainly by deleting pictures in-camera).

The proper procedure is to use a USB card reader to connect the camera's memory card directly to the computer's USB slot. IF the pictures still do not show up, they're lost. Format the card. If errors come up, throw away the card and buy a new one. Format the new one before shooting. After a day's shoot, copy all pictures to the computer and format the card at once in preparation for the next shoot. Do not show off your pictures through the camera and don't let the pictures stay there too long. As you have already discovered, the memory card is not a permanent storage device.