This is what I suggest you to do:
1. Remove the Delta 44 PCI-card physically (do this very carefully, read the instructions in your manual before doing this).
2. Reinstall Windows XP, and with "reinstalling" I mean remove the NTFS partition on which you installed Windows XP, i.e. your C-partition, and create a new one (you can all do this during the installation of Windows XP). So, do not just re-format your existing C-partition, but delete it and create a new one.
3. Ones your installation is finished, install all Critical Updates with Windows Update (this will take some time because some critical updates you have to install seperately from the others). Check the Critical Updates with Windows Update until there are none left so you know you installed them all.
4. Download the LATEST DRIVER for your Delta 44 soundcard. I checked the m-audio website and the latest driver dates from December 26, 2003.
5. Shutdown your system, open your case, and put your Delta 44 PCI-card in a free PCI-slot (again, do this very carefully). Check whether there is no dust in that free PCI-slot. Make sure it is not next to your network-card (it is known that in some cases a network-card interferes a soundcard causing noise when using that soundcard).
6. Restart your system and install the latest driver. Make sure there is no anti-virus program running in the background during this installation.