Just make sure you do a restore to factory settings. That will make the router as if it came from the factory. Also make sure that you pick a good password for the router and that you do not leave it laying around for prying eyes to find. The link below will help you with a good random password, the problem with that link is the password is long and I do not know many who can remember a number that long so you have to store it somewhere just in case. To test the randomness of the page just click refresh and each time it will give 3 new passwords. Feel free to read about how the passwords are being generated. Kind of fascinating.
This should keep the router from being hijacked. Now you need to make sure all puters hooked to it are virus free. The statement " We get redirected every link we try to go to, certain programs will not
work (getting unknown errors, or simply not running properly), viruses
infect our computers as they please (specifically a fake windows
security alert. Usually it renders everything useless and a system
restore is required. Manually finding and eliminating it does not work, makes me think that you have more then just a router hijacking problem. After resetting the router and setting a new password make sure each puter is clean before connecting to the router.
The link below will help you determine the effectiveness of the 2 AV programs you have.
You want to look at Retrospective/Proactive Test May 2011 to determine how well the AV programs detect Malware not in the virus data base. That means, in my opinion, how well it stops malware that is new and not know to the data bases. This is something you should research if you suspect that. On-Demand Comparative test show how well they detect the know virus. If you compare the results you will see that all of them catch the known virus in the high 90% range. The unknown stuff detection will fall to the high 50% range and make a dramatic fall off as they compare AV programs. Refer to page 4 of the Retrospective/Proactive Test May 2011 for the chart. Making sure that your puters are clean is the key once you reset the router and install a new password. I would only connect one at a time and use it for a day or 2 before hooking up the next one to help narrow it down in case one still has an infection. The other thing I would question is does the DSL or Broadband modem have a built in firewall. That helps tremendously. Call your provider or go to their site and research that. If it does, that should be stopping all unsolicited attacks, meaning that someone is pinging your modem and attacking thru it. After that you have to make sure that you have a good firewall installed on each puter. I can not help you much there because there is not a good site to do comparisons. I judge the firewall on puters by how easy it is to see and modify the whitelist and blacklist. I also like to have the ability to tell the firewall that a program has to ask to access the internet. In other words. I can tell the firewall one of 3 things. A program is blocked from accessing the internet. A program must ask permission to access the internet. A program has permission to access the internet. On my puter only 3 programs has direct permission to access the internet, my browser, host process for windows services, my chat program. I have 4 that must ask before accessing the internet. I block over 60 from any access at all. The link below will tell you how good the modem firewall is if it has one. The final result should be stealth. You will see what I mean when you run the test.
I hope this is not to long worded, but you ask if that will fix it. This I can not answer, I do know that if you use WPA encryption and a good password, the only people who will crack the wireless connection are the super freak crackers and I do not know if any of them live near you. lol Also you might be fighting a 2 prong battle, that is why I suggested that you check your machines and the AV and firewall programs. In the end I can only make suggestions based on prior experiences and hope they help you dig thru it. I wish you luck.
One last thought might help you determine where and how the problem is occurring. Bypass the router and hook only one machine at a time to the modem thru the LAN port and use that way for a day or 2. If none of the puters have problems and then you hook up the router and they come back then something is really wrong.