From the Windows machine, try running this and see what you get:
telnet 192.168.1.150 3306
You should get some garbage characters back. (You can close the connection using CTRL-Z)
If that works, try installing the MySQL GUI tools on your windows box and connect to the database using them. You will probably have to add your Windows IP address as an allowed root host in MySQL.
Finally, look at the the hosts file on the Windows machine, and on the Debian machine. An invalid hosts file can cause strange communications problems like what you are seeing. You can post the hosts files if the error is not obvious.
One more thought - try turning off IPv6 in Windows 7 - it is on by default.