backup the seed by writing it down on a piece of paper. then upgrade to the latest version of electrum. it may be that the bug you have encountered has already been fixed.
if the above doesn't work then I suggest restoring your wallet via the seed. Use file > new/restore to begin the process.
I am using Electrum 2.7.14 which is the latest version. And I can't restore my wallet from seed as there has a box says "please wait" which stay there forever after I have entered the seed.
Is there a way to uninstall Electrum completely? I tried to uninstall and reinstall it once but everything came back in place.
Or is there anyway I can move my wallet to another wallet client?
Thanks.