NOOB ALERT - Cannot obtain a lock on directory core is probably running access denied?

Hi i recently downloaded the core, bought some litecoins and sent them to the wallet. as the payment was pending i thought id sort out security of the wallet so i encrypted it with a passphrase. it automatically closed and now it wont open. ive reset computer, checked task manager and there isnt another open. are my newly bought coins lost in the ether? and if they are how do i go about re-installing the wallet without having to sync again, and how can i avoid this from happening again?
Thanks in advance,
a noob