i use the thompson speed touch 545 router to connect my pcs to the internet which is broadband every was working fine for a couple of months and then suddenly the router stops working and i cant connect to the internet ,theres a flashing light on the router called Line Sync could anyone tell me what this means and if this was some kind of attack on the router that has brought it down

ive tried several times to get the router connecting to the broadband service and it worked a few weeks ago for a day and then stoped again whith the flashing Line Sync. The actual broadband telephone line is fine as i have checked it so its difinitely the router any help thanx