Have you tried changing your driver settings? I.e. disabling driver enforced anti-aliasing. To be safe, your video driver should not be enforcing any kind of specific rendering. Everything should be left to application-based settings to prevent conflicts.
Also can you give us your system specifications? You can do so by holding down your Windows Key + R to open a run console, type dxdiag, click OK. Once it opens, click "Save All Information" and post the log into this thread.
Something you may also want to check is if your IDE or SATA controller is set for PIO mode instead of DMA. Do Windows Key + Pause to open the computer properties window, go to device manager, expand the IDE ATA/ATAPI Controllers, double click all of the devices you see there one at a time to open their properties, check if it has an advanced setting (if not that is fine, it means DMA is automatically enabled, just close it out), and ensure "DMA" or "Ultra DMA" is enabled. Can save you 30% of your CPU usage.