Quote from: Kapteiner on January 07, 2020, 06:45:25 PM

n2VNuEYFAez1sxt3BnQFHB8dsFbsq5iLR
mqkQHLvKjjmG9GDn5J1q8WxeqcrL9sqe6
moD8GJifDAZDAYQ1H4fBtoSwvUWcLqnXt

The above addresses are related to testnet addresses. What it has to do with mainnet addresses which starts with 1,3 or bc1? Huh

Quote from: Kapteiner on January 07, 2020, 06:45:25 PM

p2pkh:cNoMrMo7EXASV2j3ggUCnFWXrcTryUsTmJyt21tn1114VNqzjs
p2pkh:cRUFouVDhhRSPMF8yHU7SPhs6qnXcc4mqxADNDiYrK5fq6uL39
p2pkh:cR8zQwJ4Dz5AtvZnW6dqKkiSRoJWXXfPtFE4UvsNc2Zwx8Bav2C

Testnet private keys starts with character 'c' Are you trying to send bitcoin from mainnet to testnet wallets or the vice versa? Either of them is impossible to do so as both have a separate chain and note that Testnet coins has no value in real world!

Privkeys with uncompressed pubkeys start with character '9' and Privkeys with compressed pubkeys start with character 'c' which is the one you have mentioned!

Quote from: MagicByt3 on January 07, 2020, 07:22:20 PM

I have seen this error with altcoins before or trying to send to a NON Bitcoin address.

This. If you try to send btc from a mainnet to testnet or any other non-bitcoin addresses you would encounter this issue. See this issue : "Pay to" in "Send" tab detects invalid address: Invalid Lines found #3427

Quote from: Kapteiner on January 07, 2020, 06:45:25 PM

2. How do i import it to use it?

You should have accidentally logged into a testnet wallet and should be having this problem.

Quote from: Kapteiner on January 07, 2020, 06:45:25 PM

3. Is there anything i can do? I suspect its a virus maybe?

The issue is not related to virus. Rather you should be logging in a mainnet wallet and should sweep the coins.

P.S Never deal with newbies/forum users who ask for private keys in PMs or trying to assist you through PM.