It's less likely to be a virus than running the processor at 100% for long periods when rendering :(

Make sure you have a good AV (paid or free) from Norton/Mcaffee/AVG/Avast or any other big player and keep it up to date. You can scan you old HD without triggering any virus activity before installing stuff.

As above, make sure you're not blocking the vents underneath or fan with fluff. Simple stands or stands with fan power are available. They also put the keyboard at a better angle for typing. There are free apps available to monitor the cpu temp and fan speed

Poser 11 , 180Gb in 8 Runtimes, PaintShop Pro 9
Windows 7 64 bit, Avast AV, Comodo Firewall
Intel Q9550 Quad Core cpu,  16Gb RAM, 250Gb + 250Gb +160Gb HD, GeForce GTX 1060