Good Question.

At the very moment multiple coins they deal in start taking off, they do a server upgrade. Marvellous!
BUT I do like CoinsMarkets. All users make sure to check out their 'Stake' page.

On the virus question... I expect they are false positives. I get them often on all sorts of software.
Electra wallet hasn't triggered anything on my system and I run a lot of anti-malware and anti-virus stuff.
But hey... I don't know for certain.