Limited or no connetivity

At first it happened once in a blue moon so we ignored it but now its happening at least once a week and its really starting to frustrate me i can be doing anything at all on the internet and it will just crash the modem stays on but the computer and all other computers connected to it loose internet connectivity and it stays like that until we reboot our modem anyone got any idea how to fix this?

 

I can think of three things.
1) a bad connection.
2) update the router firmware.
3) you have an infection.
make sure all wires are secure, and scan all pc's for infection.