Firefox - vyhladavac

I was having the exact same problem, and for me it was a DNS setting

1-go to Start > Control Panel > View Network Status and Tasks
2-in the second "section" (under view your active networks) click on the Connection name beside Connection:
3-in the popup, click properties.
4-click internet protocol version 4, then click on properties
5-select the option to "Obtain DNS server address automatically" (the DNS server locations that are entered are from comodo)
6-click ok.

This worked for me, not only can I search normally like I used to, but comodo still works ^-^

Good luck!