Hi, Need some help.

I recently had installed ethernet cables to four rooms in the house.  Using a TL-SG108E switch.  When I run some of the house deciveson Ethernet the devices still on Wifi can be effected.  Mainly my work laptop which drops on both wifi and also ethernet if I plug it in.  Strange as my gaming desktop using the same cable does not get affected.  Also, the heating app on my Iphone (Netatmo) will not connect to the heating switch which runs on wifi.  If I disconnect the switch and rely on wifi again the heating app on the Iphone connects to the switch for the boiler no problem. 

Something is causing a conflict ?  The router is running on DCHP and all the devices seem to be on individual IP addresses.  I know its not the swtich and it has to be a router issue but anyone come across this before ?  Router is a Sky box.

Thanks

Damian