Doing this involves editing the registry, it is recommended to do a manual system restore point before doing this.
You will need to make a file called gestures.reg, open notepad and paste the following:
Windows Registry Editor Version 5.00
[HKEY_CURRENT_USER\Software\Synaptics\SynTPEnh\ZoneConfig\TouchPadPS2\Right Edge Pull]
"ActionType"=dword:00000000
[HKEY_CURRENT_USER\Software\Synaptics\SynTPEnh\ZoneConfig\TouchPadPS2\Left Edge Pull]
"ActionType"=dword:00000000
[HKEY_CURRENT_USER\Software\Synaptics\SynTPEnh\ZoneConfig\TouchPadPS2\Right Edge Pull Extended Zone]
"ActionType"=dword:00000000
[HKEY_CURRENT_USER\Software\Synaptics\SynTPEnh\ZoneConfig\TouchPadPS2\Top Edge Pull]
"ActionType"=dword:00000000
Save this file somewhere, with the .reg extension.
Now run it, some warning boxes may come up, you will need to press Yes when they do, after the operation has finished, reboot your PC and they should now be disabled.
If you want to re-enable these gestures, then you will need to do the same but use the following text when saving the file:
Windows Registry Editor Version 5.00
[HKEY_CURRENT_USER\Software\Synaptics\SynTPEnh\ZoneConfig\TouchPadPS2\Right Edge Pull]
"ActionType"=dword:00000002
[HKEY_CURRENT_USER\Software\Synaptics\SynTPEnh\ZoneConfig\TouchPadPS2\Left Edge Pull]
"ActionType"=dword:00000002
[HKEY_CURRENT_USER\Software\Synaptics\SynTPEnh\ZoneConfig\TouchPadPS2\Right Edge Pull Extended Zone]
"ActionType"=dword:00000002
[HKEY_CURRENT_USER\Software\Synaptics\SynTPEnh\ZoneConfig\TouchPadPS2\Top Edge Pull]
"ActionType"=dword:00000002
Windows 8 now has touch gestures which are available on multi touch trackpads. If you slide your finger in from the right of the trackpad the charms menu will likely appear. It happens to me a lot as well. Another thing that happens with me is the start menu popping up. This is because if you open the charms menu via a gesture and then let go, the start menu will open as it is selected by default. Give it a try and see if it is what you are experiencing. If so you might just want to disable that gesture.
Have a look at your mouse settings in Control Panel. There will likely be a setting which modifies how the trackpad can be used. It is different for each driver so I can't give you very specific instructions.
This may be a solution for you: how do i turn off windows 8 gestures or on Superuser (a related question)
Best Answer
I tried to achieve this before asking the question you are linking to. After playing around in the registry for some time, I think I have found the solution!
HKEY_CURRENT_USER\Software\Synaptics\SynTPEnh\ZoneConfig\TouchPadPS2_3\or something similar. It may be a bit different depending on driver version, vendor etc.
Example:
Here I have modified the Top Edge Pull-zone to not go so far down from the edge. The value I need to change is the LoYRel. The higher the value, the smaller the zone ("how far from the bottom the lower part of the zone should end"). I've changed it to be ffffffff (the max) which means that it will only do a Top Edge Pull when I start with my finger entirely from the top edge, and not when I start closer to the middle. The default value was fffff060 which left some (too much) room on the top, now I don't accidentally do edge gestures/swipe all the time.
NB!
When playing around with the values, don't set them too extreme just to check if you're editing the right value. I managed to make my entire touchpad an edge-zone. :p