What motherboard do you have? If you don't know, open up the case and look, or reboot and enter the BIOS and look for the model information. Who built this PC? You should have been provided some sort of list of the hardware used.
The other hardware is pretty easy to figure out - go to the device manager and look at the video card, audio, etc - then just visit the manufacturer's website and download the drivers for your hardware.
There's an existing thread in here about the "server execution failed" message, as I posted in it recently. Check it out to see if that helps. Windows 7 Ultimate x64, Multiple Problems
For the slowness, I believe that it's a combination of incorrect drivers and possibly the virus again - especially if you accessed drives/discs/etc (that were connected to your system while you had the virus) before you installed anti-virus software after installing Windows 7 again.