If you installed electrum your wallet will be in:
~/.electrum for Linux (backup entire folder if possible)
%appdata%/local/electrum or %appdata%/roaming/electrum
If it's standalone then look for the electrum_data directory in the same directory as the electrum bin/exe.
Since OP said it's Windows, let's not confuse him with Linux. So I crossed out the part that's not useful.
Now, together with the backup, OP should also make sure what kind of
Electrum install he had and for that looking for these folders to find his data is just great.
I'm telling this because if he wants to have it running without other intervention after install, it's best to have the same install type. (I expect it's a proper install with Windows Installer.)
And BTW, uninstall is not advised. Just backup the wallets and install the new version over the old one.