New
#11
Visit malwarebytes.com and download install and scan that system with it.
No antivirus is Windows PC suicide if connected to the internet.
Looked mobo up and it was pretty sweet back in 2007:
XFX nForce 780i SLI Motherboard Review - Power Consumption and Conclusion - Legit Reviews
I suspect problem with BIOS upgrades is due to what looks like XFXforce getting out of the motherboard making business a while ago and being that old, way out of any life cycle requirement of support.
Here is the drivers suite from Nvidia though:
NVIDIA DRIVERS 15.58WHQL
If willing to pay, this outfit handles BIOS updating:
http://biosagentplus.com/
I'd at least install it's scanner to see if one is available.