One thing to check is whether or not you still have the password / passphrase for your wallet. Everyone should have already checked this already well before the deadline however there is likely people who still dont know how or simply have not because they think the process is too difficult.
I do this using geth on a spare linux computer I use for cryptocurrency however it is possible to check using MyEtherWallet.com which might be easier for some. Here are the steps:
- open MyEtherWallet.com
- click "view wallet info"
- select "Keystore / JSON File"
- click "select wallet file"
- navigate to where you have the wallet file stored and open it
a password box will appear on the page, enter your password and click unlock
wait, this may take some time. For me testing with a wallet I just generated firefox slows down while it is working and pops up a box saying the script is unresponsive, just click continue to let it keep decrypting the file. It did this a couple of times then displayed the details of the wallet including the private key. If it can do this then your password is correct and you will be able to control any funds associated with the account REP, ETH etc