Does cool math games website give viruses

Yes, some part of their site, be it games, ads, or other content, I think passes along viruses. After using some of their content, my machine locked up full of viruses as was told to me by the repair shop. One instance such as this alerts a person but not to the extent that one could pinpoint the virus.
However, I gave the site address to a friend of mine about three weeks ago. He has three children and they really got into the games. Unfortunately, he called yesterday and said his machine was virus laden.
Both my machine and my friend's machine were used for a number of years with little change in their use until Coolmath was introduced.
Within three weeks of use of the new introduction, the second machine was locked up.
I gave you the total picture so you can make your own mind up, but I don't use Coolmath anymore.
WB