I'm not sure if you're trolling or not, but 200 bitcoins is currently worth ~2,357,000$. ( Which seems to pretty aligned with the number you are giving.)
There's no virus/scam or bug, the price simply increased. Congratulations.
I'd advise you to make a backup of the private key of the adress you're currently storing the 200 bitcoins on, and either memorize it, or hide it, in case your old PC / ( the harddrive of your old pc) breaks.
Or even better, buy a hardware wallet (such as a trezor or Ledger Nano S) Or a secure new PC/Laptop, and store the bitcoins on there.
thanks, is coinbase a good place to sell? – 2523454 – 2017-12-05T16:10:34.060
Not necessarily "good", ( in terms of fees), but it is a safe and secure place to sell your bitcoins, yes. – Rutger Versteegden – 2017-12-05T17:38:13.807
By transferring funds from Coinbase to the "sister site" GDAX, and by using a "limit" order you can avoid pretty much all the fees: https://www.youtube.com/watch?v=JNH3AFRatrM Or you could send the BTC to GDAX directly. (Note that if the OP truly has 200 BTC to sell it may take a long time to withdraw the funds… I've never had to take that into consideration ;-)
– natevw – 2017-12-05T19:46:56.473