graphics card conflict

I have bought and installed a Geforce 4 MX440 graphics card (64 mB SD ram ), but the computer , a MYCOM 1000hz, with 256 mB ram , can’t find it . The old card is an onboard Savage 3 card and this may be the problem . Can I just uninstall the onboardcard , or is this a bios related problem ? How should I proceed ?