Salam to All

Please yaar kiya koi mujhay bata saktay hai k VIRTAUL MEMOERY kiya hai?
Aur iss ko increase kasay kiya ja sakta hai?
Meay system hain 3 GHZ ka Processor ha 512 ki RAM hai but phir bhi baar baar LOW VIRTUAL MEMORY ka ERROR ata hai. KIYA KERON

Please tell

Adeel