My internet connection through wl-500g gets dropped from time to time, and I had to reset it by powering off and on. But my router is not easily accessible. Is there a way to reset the router from remote? If so, where can I find the information?

not sure if you are doing it right
your wireless router has 2 "sides" one is it's upload, it's wan network and that is where you should set DHCP - so that the router itself gets an ip from your LAN
other side is behind your wireless router and there DHCP should also be off. it would be best if you could put your router in bridged mode - just to extend your network over WIFI

reset the router, push the tiny reset button. If it doesn't work, call your ISP (if it's a modem/router) ...or if it's a secondary router, get a new one?

Have you tried to reset the router? Most routers have a reset button in the back of the router (where the LAN ports are located) that you can hold in for ~30 seconds to reset the router to factory defaults which could also resolve the issue you're having as well. Although if you have a computer connected using a patch cable (CAT5) to a computer that is turned on and your not getting a link indicator light on your router then try another port to see if the led is visible then, if not try another patch cable or try connecting it to another machine.

check the setting of the wireless

Try connecting directly to internet via modem, you may need to configure your router read documentation that came with router or search for user manual online.

I had the same problem and found the solution here (last post):
http://wl500g.info/showthread.php?t=11077

Short answer: "the power supply is faulty"

Usually the MAC is on a sticker somewhere on the router, but your ISP should also be able to detect it.

You need to contact your ISP if the internet connection is not there....

maybe there some incompatibilities in your other router. or the kind of cable you are using. or it is incompatible with your other devices.

My advice and personal experiences with both wired and wireless connectivity, is if you wish to share files and internet connection, purchase a combined Modem/Router and not a seperate router to work along side your original modem. Your modem will send your router an ip address in turn your pc is sent one from your router and can get complicated; keep it simple! These are much easier to set up and control as one unit and if there are ever any connection problems you will know it's either a setting or a modem/router problem and not have to wonder ; is it the modem?; Router? settings? etc. As there are frequent loss of connections both internet and LAN it makes sense have one peice of equipment to maintain.