You mentioned above "...my desktop computer has no problem, it works fine, the internet connection has never failed."
It sounds like your laptop has problems when coming out of standby and sleep; the WiFi card does not re-initialize properly. Maybe a BIOS update would fix this?
You have several scenarios going on here at once. The best/fastest/most secure configuration is WPA2 Only and AES encryption; this is what D-Link recommends. If you have older devices that can't find your wireless network with this setting; then you might want to try WPA and TKIP. My Aunt has some older WiFi devices that don't like "WPA2 Only", which does what it says. Only WPA2 can get in; everything else is denied access.
I'm not 100% sure what Auto really does; someone else may know this feature better. It either switches to WPA when it finds a device that doesn't like WPA2, or maybe it works with both at once. Anything other than WPA2 and AES is going to be slightly slower, and less secure. But if you can't use that; stick with WPA and TKIP and see how it works.