Wifi and sound whats the problem?

At random moments during the day when i use my laptop i will notice that the internet will just completely crash for me. My wi-fi connection shows my available connections but no internet access. When i reboot the laptop everything is back to normal again. It's just extremely irritating to have to restart my computer every hour or so and also i am extremely paranoid that i've lost connection every 20 minutes. Also the same thing happens with my speakers they die yet once i restart the computer everything is good to go. This is extremely amusing to me because i sent my computer to Dell for repairs because my sound card wasn't picking up and my wifi could not connect either. It's just seem to have gotten progressively worse even with the new hardware that was installed.