I have A thomson rca dhg535 from comcast.I disconnected the box to move it.After I reconnected it, all the lights came on,but the link light keeps blinking

You are trying to connect to a modem, not a router, the router, a wi-fi version, is what you are connecting to your network.
First, power off all equipment, computer and modem, use the network cable you have connected to your computer from this modem and disconnect from the computer, connect it to the differently colored port on one end of the Belkin, the others have numbers, connect a network cable from one of the numbered ports to the computer.
Now power on the RCA modem, wait until lights are steady, then turn on the new Belkin router, wait until lights are active, just a few moments, then power on your computer, you should now have internet access and be able to locate the manual from the Belkin's website to further your setting up a passphrase or setting up some security on your wi-fi.

Here's the manual from a Google search:

https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=2&ved=0ahUKEwiG7fidjsXZAhWHrFkKHb5BDfMQFggzMAE&url=http%3A%2F%2Farmstrongonewire.com%2FContent%2FDocuments%2Fdhg535_manual.pdf&usg=AOvVaw156GN98d9vEu7NhtJ48NBL

There should be a tiny button that you can press with a toothpick on the back side of your router. Press it for 5-6 seconds and wait untill it restarts. Thomson routers in general takes long to restart so maybe you wait for about 3-5 minutes.

Change the cable!

Hi,

It can be an issue with the modem or with the line. When the line drops the link then the modem shows only two lights. And, when you power cycle the modem (unplug and replug it) it establish the session again with the comcast.

So, i'll suggest you to get the line checked first and if comcast finds that line is working fine then get the modem replaced.

Rashish

looking at the internal modem page.usually:192.168.100.1. on your browser.explorer works best for this look up. you dont need internet access for this. once inside you can look at signal strength coming from the street and signal going back. if its out of spec.then that needs to be corrected. Note :call your provider and ask for down/up stream
specifications. also weather or not your modem is ( EOL) End of life.
Good Luck.

It sounds like the LInksys that they replaced was also a router. A router will route packets to multiple pc's that are connected to it. The cable modem just sees the router as 1 pc. When you use a switch, the cable modem will see all of your PC's. and Comcast just allows 1 pc. You will need to buy a router to use more than 1 PC which will be cheaper than using Comcasts Home Networking service which will network up to 4 pcs

Do a powercycle. Make sure to completely turn off the modem, router, after 30 seconds, turn on the modem first then the router.
If that will still not work, perhaps there is a need to update the software of your router.

This might help:

http://linksys.custhelp.com/cgi-bin/linksys.cfg/php/enduser/std_adp.php?p_faqid=3686&p_created=1151377023&p_sid=Z6gSExfj&p_accessibility=0&p_lva=3687&p_sp=cF9zcmNoPTEmcF9zb3J0X2J5PSZwX2dyaWRzb3J0PSZwX3Jvd19jbnQ9MTEyJnBfcHJvZHM9MCZwX2NhdHM9MTcyMSwxNzIzJnBfcHY9JnBfY3Y9Mi4xNzIzJnBfc2NmX2xhbmc9MSZwX3BhZ2U9MSZwX3NlYXJjaF90ZXh0PXdydDU0Zw**&p_li=&p_topview=1

If you haven't already done so, contact your cable provider and let them know what is going on. There may be a signal issue and your modem is losing its lock on the carrier.