OK then let's talk resources. Go to start>run and type RSRCMTR press enter to start Resource Meter. Graphics programs can use resources quickly. You may not realize it at the time.
Monitor how low they are.
To limit the amount of resources being used at Start
Run startup log
Download it here:
http://home.earthlink.net/~rmbox/Reticulated/Toys.html
It will generate a text file with a list of all startups.
Go to this site and compare to the list to see what is not needed. Prune your startups.
http://www.pacs-portal.co.uk/startup_content.htm
You say you are having freezes? On the internet or off? Do they coincide with the memory messages? Or not?
Please post your system specs.
Freezes can mean many things.