Monitor or graphics card problem

Hi, my friend just bought a new hard drive, his old hard drive contains windows 98, and that configuration allowed him to view on different resolutions and have the option for more colours, but this new hard drive, when installing windows 98, will only give him two options ofthe colour settings, either 2 bit or 16 bit, and he only has the resolution 600x800 available to him. I knew there was a trick to over-coming this problem but i can't remember how to do it. Is there anyone that can offer any solution to allow him to have more colours and a better resolution?

If it matters any or is revelant the operating system he has on it is windows 98 SE.

Thanks in advance.