When...is it making the noise?
At boot, when Windows loads, after the Desktop appears, etc.?
Need more specific info, please.
If it's after the Desktop appears, can you use the computer?
Can you go to Control Panel | Sounds and Audio devices | Sounds tab?
If so, use the lower of the two "down" arrows 'til you get to "Open program".
Click that, then click the button near the bottom with the arrow that points
to the right. Is that the "dodo" noise you're hearing? If not, try some
others. (Only the ones with a "speaker" symbol beside them are currently in
use for your setup.)
Maybe it's the "New Mail Notification" sound?
It would help to identify the exact sound, and the event(s) occurring at
the time that you hear it.