pc help

[hammerhead]

im no expert on pc just know the basics but my pc is coming up that my vitual memory is running low? i checked the hard drive and still have about 47 gig left on it and when i have it on i have fire fox with 3 tabs open at the most possibly msn butive tried it with just max bashing on and no msn and its still flashing up what am i doing or not doing right havent downloaded any thing unusual just skype recently but thats now uninstalled with any other unsed items in the control pannel.
ive de fraged it and done a dyagnostic check and all sais fine any help would be great cheers


steve