using old router up stairs along side new router downstairs?

hi again, i had a new router turn up from talk talk as the last one we had was a few years old but still works fine. i am wondering since i have new router downstairs can i use the old router upstairs so we have a good solid signal through all of house? if so what is the best method for this as the routers both have different names and passwords which isnt a issue but what i am concerned about is will this mean depending on what router is strong at the time the internet on a device will flick between the two routers meaning loss of signal and defeat my aim?

thanks

i will have a look online and check out signal boosters thanks for help

Yes it's easy to set up the secondary router as a wireless access point but you would need to run an Ethernet cable to the desired location for the secondary router. Double NAT, repeat IP's, default gateway's etc. is not going to be a problem once you turn off DHCP on the secondary router.

Yes it can increase signal strength where the signal was weak using just one router, the secondary router can cover the rest of the house. This is standard procedure for setting up a secondary wireless A/P.

You will want to plug those routers in LAN port to LAN port then it's most important to turn off DHCP on the secondary router. Eventually the secondary router will pick up an IP from the first router. This will place everything into the first routers subnet so everything will be using the same default gateway etc.

I would take a wireless access point over any type of network bridge or wireless signal booster any day.