Junk Files and Temporary Internet Files

According to Microsoft, if you do not clean out your cookie cache, delete your history, and run Dish Cleanup at least once a week, you run the risk of overloading your system. Junk files and temporary Internet files accumulate over time as you browse the Web, and with too many in your system they can eat up all of your virtual memory.

Video, Picture and Audio files

If you have a high number of videos, pictures and audio files, this will also take up virtual memory on Vista. It is suggested that you save these files to CDs or CD-Rs to eliminate memory overload.

Viruses and Malware

Viruses, trojan horses and other malware can also take up virtual memory. By reproducing files stored on your PC (that might be transferred elsewhere), these forms of malicious code can result in computer crashes, some of which can never be repaired.

Programs

By deleting programs stored on your computer, but that you no longer use, you can increase your virtual memory considerably.

Increase your RAM

According to Microsoft, if you are receiving messages such as "virtual memory is too low," followed by your system instantly shutting down, you have memory overload. You will need to install more RAM internally or add an external hard drive to your system.

Source:

Preventing Low Memory Problems

3 Stubborn PC Problems

What Is Virtual Memory?