Click file, then receiving addresses. Find the address you sent coins to in the window that opens, right click it, and select copy address. Close the addresses window.
Click help, then debug window.
In the debug window that opens click console.
In the text box at the bottom of the window type
dumpprivkey yourAddress
where yourAddress is the address you sent coins to and copied earlier.
Press your enter key.
The private key for that address should appear in the console window. Copy it.
This is an example private key.
L48toSntMVhC2az4KAQCWscrQGfPbT55yCgzM5cmx9Ao69pTdwrq
Download and install electrum.
https://electrum.org/#download
Import your private key into it using these instructions.
http://docs.electrum.org/en/latest/faq.html#can-i-import-private-keys-from-other-bitcoin-clients
Afterwards your coins should be spendable.
Click help, then debug window.
In the debug window that opens click console.
In the text box at the bottom of the window type
dumpprivkey yourAddress
where yourAddress is the address you sent coins to and copied earlier.
Press your enter key.
The private key for that address should appear in the console window. Copy it.
This is an example private key.
L48toSntMVhC2az4KAQCWscrQGfPbT55yCgzM5cmx9Ao69pTdwrq
Download and install electrum.
https://electrum.org/#download
Import your private key into it using these instructions.
http://docs.electrum.org/en/latest/faq.html#can-i-import-private-keys-from-other-bitcoin-clients
Afterwards your coins should be spendable.
