Dell Dimension 9200
Extra memory fitted Bios shows 4gb windows shows 3.04 Anyone tell me why please?

This is a technical limitation of all 32 bit operating systems. Your computer's hardware like the video card and sound card are addressing a percentage of that memory. This is because the absolute limit is 4GB. Upgrading to Vista 64 bit will solve this problem. You should be able to call Microsoft and request a copy of the 64 bit from them. If you have already bought the 32 bit version, it should be free of charge.

Thank you very much