I think you are saying that when the router is wireless it disconnects and when you plug it in via Ethernet it never disconnects. This is a common occurrence. You might also be saying that your are bypassing the router and plugging the Ethernet from the cable or DSL modem directly into your PC. In any case you can try the diagnostics below:
First try the easy obvious fixes.
How far away are you from the wireless router when it is disconnecting? Try putting them next to each other when you are connected wirelessly. If they don't disconnect then the problem is they are too far apart. If the problem is resolved, try putting the router half as far away and see if it is OK at that distance. If the problem is a distance problem, put the router up higher or closer to your PC, or try moving the antennas around if there are antennae. This will look funny, but you can also put a sheet of aluminum foil on the side of the router opposite the PC, so the router is in between the foil and the PC, it will reflect the signal back to the router, and that might strengthen the signal enough.
It can also be interference from other electronic devices. Try putting the wireless router away from everything by at least 2 or 3 feet and see if that solves the problem.
It can also be a heat issue, make sure the wireless has enough air circulating around it. I had a router once that would overheat and then disconnect, then cool down and reconnect. I couldn't get that router to ever work correctly, it overheated often, so I upgraded to another wireless.
If none of those above helped ...
Then it has something to do with either the wireless router, or the wireless adapter on your PC. Do other devices also disconnect every hour? Can you borrow someone else laptop and see if they disconnect every hour also, if so then it is the router.
Now you have to get the router manual out because this will get a little advanced, what you want to do is update the router firmware if it needs it. First check what version of the firmware you have on the router. You can do this usually by clicking here in this browser on your PC http://192.168.1.1
if that doesn't work try this http://192.168.0.1
if that doesn't work read the manual and see what the address is to check the firmware of your router. Usually you will use your browser and type in a number similar to the one above. You will need a username and password to login to the router. Find the version number of the firmware that you have loaded on this router. Write that down.
Look at the back of the router, write down the exact model number and version of the wireless router. They usually will have a version. Now search for that model number and version and also for the words "firmware download". If this version is newer then download it to your PC. If it is newer then start the router firmware upgrade process. Plug the router directly into the PC with an Ethernet cable, connect to the router thru the Ethernet only using the 192.168.X.X address above. (probably need to disable wireless on the PC to make sure it is going thru the Ethernet). read the manual how to backup the router. Back it up to the PC if you can. Or write down all the settings and passwords on paper. But backup somehow. Double triple check you got the right firmware for the right model. Now read thoroughly how to upgrade the firmware for your model router, not always, but usually a matter of going to the right page inside the router, then click on upgrade firmware and browse to the firmware file you downloaded above. Then make sure you wait till the upgrade process is complete. Do not disturb it while it is in process. OK, now after rebooting the router check if the connection is stable.
If that didn't work then you can do a similar process for your PC and see if your wireless adapter needs to have the firmware updated, but usually it gets updated when the PC does, but check anyway.
If none of the above work, then time for a new router. Luckily they are not too expensive. If after you buy a new router you still have issues then sorry, it was probably the PC.