Tunning problem

Hi, Friends!
My problem is: Ms SQL 2000, Service Pack 2 (we should install Service Pack3), 1G RAM, database not so big- about 600M.
We have an application of our client running on it.After 15-20 minutes RAM reach the limit.
So what I can do in DB configuration to fix the problem without fixing SQL or stored procedures in application.
I'm new in Ms SQL, so every advance will be appreciated!!!!
Marina.

Rather than using dynamic memory for sql server you can specify max server memory. This was sql server will not take all the available memory.