Windows Vista Low memory on a brand new computer

[Cartmanpwnsjoo]

Hi, i got a new comp a little before christmas and it runs VERY fast, and has vista.
However i keep getting messages like : "memory is low" when the comp is clean of things that could slow it down

Also the picture keeps freezing for example: on Msn ill maximize the page and it will load VERY slowly as if there were many processes going on on the computer, when in fact there isnt

When i get this problem i restart my comp and things run smoothly for a while then say, maybe the next day, it happens again?

Could i have a virus or something?

 

[murdoch]

Computer Make & Model and System Specs would help?
Do you use any Anti-Virus software?
When did the problem first happen/appear?