I have a Dell Inspiron 3520 64-bit running Win8, and the wireless connection drops once or twice a day for no apparent reason. I have googled for solutions and have already unchecked the box "allow computer to turn off this device to save power" on my wireless adapter, but to no avail. Additional info:
What can I do to fix this and get a reliable wireless connection?
Try the latest drivers offered by your manufacturer.
If that doesn't help, then try a fresh OS/Windows install.
If those don't affect it, then based on all the other testing you did, it's probably a malfunctioning WiFi adapter in the Dell and it will need to go in for repair.
I have a Dell Mini9 that came with Ubuntu 8.10. Out of the box, Wifi configuration was done under System settings -> Network and worked straightforward. Then, after some update patches, NetworkManager was installed to replace this functionality.
Initially, it did not carry over my settings and I had to figure out how to redo it. After lots of bumbling with it, it finally works. However, after bootup the NetworkManager icon waits about 2 minutes before even attempting to connect to the wireless network. Then, about a minute later, it connects and I'm on my way.
The Mini9 boots up within 30 seconds from SSD, so opening Firefox and then waiting 3+ min for wireless networking is a bit of a pain. Can anything be done?
I have had problems like this in the past. What I found was a particular program I was running took a specific amount of time to start up. In order to not have the boot process fail, I had to insert a "wait" command at the end of one of the init.d scripts. This ensured that the application had enough time to start as the next processes to start were all dependent on the first process.
If you have a wait command somewhere in your boot process, this is how it would behave. The process would hang up until the wait command is finished and then the rest of the processes will boot normally. Check your networking components to see if one of them is using a wait command just to make sure all of the lower level processes and drivers are running first.
In Ubuntu 8.10 and even 9.04, the time for the Wi-Fi network to connect seemed very long. Since I have upgraded to Ubuntu 9.10, the time seems noticeably shorter. Maybe you need to upgrade?
In Ubuntu 8.10, I was using ndiswrapper to enable the wireless pcmcia card. The easiest thing to do to clean up that, and other, configuration customizations was to clean install. If a straight upgrade from Ubuntu 8.10 to UNR 9.10 doesn't do the trick, consider a clean install. Just keep you home directory safe, and it is pretty easy to add the account back onto the newly installed system.
As well, some netbook-oriented OSes, such as Ubuntu-Netbook Remix are setup in a way that the initial processing in init.d is performed in parallel, so that processes that have a waitning period (for hardware or explicitely) will not relay other processes, thus giving you a better overall startup time.