I have more information, but not the complete answer. I am going to make a few notes here.
TO CHANGE YOUR MODEM IN WINDOWS XP
> Control Panel > Performance and Maintenance > System > Hardware > Device Manager - click on the plus sign beside Modems to see the list and then right click on the modem, select properties, Modem Tab, uncheck "wait for dial tone before dialing"
BUT if I remember right, this will not affect AOL. You need to set the modem from AOL.
Colleen found these instructions to change the modem string, but I don't know how you are supposed to change it.
To edit the modem commands
1 On the Sign On screen, click Setup.
2 On the AOL Setup screen, click Expert Setup.
3 On the Connection Setup window, click the Devices (modems, etc.) tab.
4 Click the Modem: connection, if it is not already selected.
5 Click Edit.
6 In the Expert Edit (or Add) Modem window, click Edit Commands..
7 Type your custom modem commands in the Setup Modem String box. <<
8 Click OK.
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Use Expert Setup to
configure your modem to dial an outside phone line.
configure for pulse dialing.
turn off call waiting while you are online.
configure your modem manually.
edit the modem commands.
check for correct modem selection.