Server Memory Leaks

I have a Compaq Proliant 7000, 1gig ram, raid 5, NT 4.0 Server SP6 running Oracle. For the past 3 or 4 months I have been experincing what Compaq calls memory leaks where during a course of about 24 to 36 hrs. the performance falls to a crawl. The only way to get the performance back is to reboot the server. There only about 50 users accessing this server. Compaq says for me to reload SNMP and the lastest MS patches, but I’m not running SNMP. When I put it on and Compaq Managment Agent nothing happened. Any ideas what could help. If you need more info I will put as a response to this question.