Litecoin wallet 0 active Connections

0 connections now, but I had been using Bitcoin QT for a while without problems

This is a weird problem. I have seen it cut you off if you don't have IPv6 and the IPv4 to IPv6 virtual bridge (a service) running in the background, even if you don't have an IPv6 router nor IP and subnet address listed in your modem.

Also, if you're using Bitcoin-Qt, make sure you have the most recent version of the wallet and Pooler's CPU miner (minerd) installed, that can cause a problem too.

What I suggest doing is contacting the pool owner and find out if there is a problem with a said port and protcol, many people use Scrypt algorithm and not SHA256D anymore (unless you use ASICs) and they don't use the GETWORK protocol and port, they use the Stratum+TCP, which is default by many sites now.

This might be your problem.

Turn off or unplug your router and modem.

Drop to DOS and key this in at the prompt and hit ENTER.

ipconfig /flushdns

Plug in your modem first and wait for it to initialize and connect to the Internet.

Plug in your router and let it do it's thing and when it's up and running, type this at the command prompt and hit ENTER when done.

ipconfig /renew

After that's done type in the following and hit ENTER.

ipconfig /all

That will give you all your connection related data for a renewed adapter and cleared DNS cache.

Sometimes the cache can get old and not have the correct routing information in it which can load to "Destination is not reachable" or similar messages, like the JSON errors in the minerd.exe and ultimately Bitcoin Qt wallet with integrated mining option.