I find it concerning that nobody has asked whether your computer can still contact the router...
it has an IP address, can you ping the router?
if it has a wired port does this still work.
do the activity lights for the wired network/wireless network/internet show any traffic passing through.
does the wireless card in your computer loos connectivity with everything, is there another wireless device you could test this with.
is it just your computer that looses connectivity or are there other computers sharing that connection on the wireless LAN,
Is the wireless LAN secured?
how thick are the walls in your property, does the signal strength go from really strong to absolutly nothing, or is it weak to start with? does the weather intefeere with the radio signal?
Drivers and firmware are a routine upgrade, but they often won't fix a problem that just happens like this seems to have.