If you have done the factory reset correctly, the default IP address of the modem should be 192.168.1.1 not 10.1: Page 18
http://www.dlinkmea.com/partner/media/product_item_downloadables/9146-DSL-2750U_C1_Manual_v1.00%28ET%29.pdfPage 17 gives you steps to do a factory reset and default user name and password:
Factory Reset Button
The Router may be reset to the original factory default settings by using a ballpoint or paperclip to gently push down the reset button in the following sequence:
1. Press and hold the reset button while the device is powered off.
2. Turn on the power.
3. Wait for 10 seconds and then release the reset button.
Remember that this will wipe out any settings stored in flash memory including user account information and LAN IP settings. The device settings will be restored to the factory default IP address 192.168.1.1 and the subnet mask is 255.255.255.0, the default management Username is “admin” and the default Password is “admin.”
I would follow these steps. Ensure that your wired LAN PC is set for auto obtain IP addressing in it's networking configuration. Don't use any static IP addresses there. Ensure ALL other devices are disconnected from the modem. Once you do a reset, you should be able to log into the modems UI at 192.168.1.1 then set up a new wireless SSID name and give a new PW.