WRT54GL - constantly losing connection (not just the wireless)

Question

I have done searches here before I posted, but, in this rare case, almost TOO much information comes up, and not all of it is the exact issue that I am having, so I wanted to simply post a message and hopefully get a response or at least be directed to the proper response is already answered.
Up until about two weeks ago, I had an older WRT54TG, years old, never had any issues with it.  Then it died.  It didn't just have issues, the entire thing just died.  I didn't even care.  I more than got my money's worth out of it.  I then got a brand new WRT54GL, had no issues setting up or upgrading to the newest firmware. 
However, at LEAST once, sometimes up to four times a day, the connection vanishes.  This is not just the wireless connection, but the connection to the computer it is hardwired to.  I am forced to load up the router software and click on DHCP Renew to get it working again.  To be blunt, this is just not acceptable, and if it cannot be fixed, I will have to buy a different router.  I cannot even remember having to do this with the older router except when power went out.  Here, though, it just happens. 
Today, for example, I turned my laptop on in the morning, while upstairs, had no Internet, had to come downstairs, boot up the other computer, do the DHCP Renew just to use my laptop or any other device, again, including the primary computer that is directly connected to it.
So, that's the issue.  Any and all advice would be more appreciated than you know. 
Thank you!

Answer 1

As you upgraded the router's firmware,I would suggest you to reset the router and reconfigure it from the scratch... On the setup page of the router,reduce the MTU value to 1350.Under the Wireless tab,Change the Wireless Channel to 11-2.462GHz.Under the Advance Wireless Settings,Change the Beacon Interval to 75,Change the Fragmentation Threshold to 2304,Change the RTS Threshold to 2304 and Click on Save Settings...Now,power cycle the entire network.