IIRC for the PC version the F1-F3 keys switch between weapon sets. Could you have accidentally hit one of the keys and switched to an unassigned set?
I have the Xbox version, where you automatically switch between melee weapons and a bow using an associated attack or skill. There is no way to switch from a melee weapon to an unarmed attack without specifically unequipping the weapon.
If you did loose the sword, try emailing support@larian.com, with a description of the problem and maybe a link to this topic. See the appropriate support page for
DKS or
FoV. While they may not be able to restore the sword, it couldn't hurt to include the quicksave. Unless you found some awesome loot you want to keep, though, it would be faster to just replay the last hour. You could get a new sword, but if you continue playing in a save that had some weird glitch, I don't know if that would make possible future glitches more likely, or not.
In XP the saves are in the folder
C:\Documents and Settings\ %username% \Local Settings\Application Data\Divinity 2\Savegames
or in Vista / Win 7
C:\Users\ %username% \AppData\Local\Divinity 2\Savegames
You may need to set Windows Explorer to show hidden files and folders (
XP, Vista,
Win 7).
