The "Virtual Memory" is the Swap File or Page File - a section of the hard drive that Windows uses to augment the PC's RAM when it needs more memory than the RAM provides. Lower priority processing is temporarily transferred to the Page File. This happens in all PCs but your Page File setting may be too low or you have insufficient free space on the hard drive.
Right click "My Computer", select Properties and then the Advanced tab. In the top "Performance" section, click the Settings button. In the Performance Options box that opens, select the Advanced tab and in the Virtual Memory section at the bottom, click the Change button.
The recommendation always used to be an initial size of 1½ times the PC's RAM and a maximum of 3 times, but with very large amounts of RAM in a PC, this can become excessive. Try using the "System Managed Size" option.