My front dual USB port is broken on my old PC, ie it consists of a gaping hole with distorted pins inside (on the inside, it's still plugged on the motherboard, in fact, it's welded on it). I have kids, and in order to avoid short circuit problems, I want to fill it up with a glue gun. Could it cause any electronical trouble?
As Transistor says, hot glue will work fine. Just be careful that you don't inadvertantly glue the housing to the panel opening in the PC.
Hot glue is actually better than the comments (IMHO), because you can fill the opening and make it very clear that the port doesn't work. For instance, if you pull the pins, there is nothing to keep a user from inserting a thumb drive into the port and then go crazy trying to figure out why it doesn't work.
Hot melt glue should be fine as it has low electrical conductivity and does not generally absorb moisture which would be a problem. It will be difficult to make a nice finish.
Wikipedia's Hot-melt adhesive may be worth a read.