I use Beyond Remote version 1.2.1.531 >http://rapidshare.com/files/158140526/beyondremotefull.zip.html
You have to install it on both computers.
Once installed, on your Mom's computer, the Beyond Remote Server Icon will be down by the clock. Double cick on it and write down the local IP address.
Then on your PC, start Beyond Remote Client and then, click Manager/New Remote Computer and check the box for Beyonde Remote Connection.
For Connection name put whatever (Mom's PC).
For Server Name IP address put the IP address of your Mom's computer you wrote down. Then hit OK.
Now highlight your newly made Remote PC connection and click Connect. If all is good a password box will come up. Put in the password you used when installing it and hit Connect. In a few moments your should be looking at the desktop of the other PC on your screen in a window. You can control the mouse just as if you were sitting right at it.
If it does not connect, then it's possible the Firewall is on on your Mom's PC and you will either have to make an exception for Beyond Remote to pass through the firewall or shut the firewall down completely.
When viewing the other PC right click at the very top left of the window, and a bunch of setting will pop up, like Send Ctrl/Alt/Delete, and lock remote mouse, etc...
Hope this helps!