I also used to have similar malfunctions with that "modem" and i asked from CYTA to provide me a brand new modem and they did that. So just request a new one

Who's deleting the posts? If anybody don't want my appearance here, no problem......

Connect the devices the way you describe (use crossover cable for correct connection between two routers) and disable the DHCP on Linksys router.Also change the IP of the Linksys router(static) into an IP address in the range of your networks IP addresses, be careful not duplicating any IP address. You have to use Linksys router as wifi access point and also as Ethernet switch, disabling DHCP makes the Linksys router act like switch.
I 've never implement that solution but i think that this may work.
Making search on the internet may help you solving this problem. What you want to search for is " how to turn a Linksys router into wifi access point".
I hope that was helpful.

Can you be more specific please? The adsl modem your client got, supports wifi or not? From what you describe i understanded that at ground floor theres an STB which is connected to the adsl modem on first floor with Ethernet cable and also there is a PC on second floor which is the one you want to have wifi connectivity with the adsl modem, am i correct?

Hi guys,
I'm new here i have a similar problem , i thing so, I'm trying to configure my netgear adsl router to use it as my internet access device instead of THOMSON TG585 v7 which is my providers router. Can anyone had the same problem and solve it(I mean using a router different from the one that CYTA provides)?