WHY DOES MY SPEEDTOUCH 576 BLOCK EVERYTHING?

If I connect the router to the PC with ethernet cable all is fine, If I connect the router to my Slingbox,XBOX the speedtouch does not detect it let alone let me access servers.

HELP?? I have set DHCP and static IPs on all devices but no good no devices are detected by the router

I have set DHCP and static IPs on all devices

Well which one?
Have you set the devices to automatically obtain IP address and DNS details, or have you set them static?

speedtouch does not detect it let alone let me access servers

Many routers only display connected devices that are using its DHCP server, so if the devices are static, they may not appear in the listings on the Speedtouch.

Which servers? Ones in the devices, or are the devices not accessing the internet?

I have done both, but nothing has worked. The slinbox for example connects to another server in order to send TV over the net, but it doesn't connect, same with the satellite receiver, it connects to the manufacturers server to update software but no good, Infact when you hit update the ethernet light goes off

Could be a dodgy router.
Could be you haven't set up the firewall rules properly (what ports & protocols does the Slingbox use? Do you need to set them up the the firewall?).

If you're using static IPs (in the devices) have you also set up the correct subnet mask (i.e. 255.255.255.0) & default gateway (the router IP), are the device and router in the same IP range, and have you also entered the correct DNS addresses (that of your ISP, or any other DNS you may be using)?

If you are using static addresses, have you also set the Netmask and Gateway addresses correctly?