Ac adapter = unknown device installed - Amstron Dell Latitude D520 Laptop AC Power Adapter (4.3A 75Watts) by Amstron (Generic) AC Adapter

What is a screencard? I think they mean display driver, try uninstalling Display Adapter and then reinstalling sometime fixes problems.

Welcome to the Community. Press the F2 key at the Dell Logo on startup to load into the Bios, and check what does it say next to AC adapter, if it says unknown, try another working adapter. If the working adapter works then its an issue with your ac adapter, if it says unknown in the BIOS then its a motherboard failure. Still having Problem Then follow Us For
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Check the system battery information and charger information of the computer restart the computer, while the computer is booting up, press F2 repeatedly check "battery info"
If it stated ac adapter = unknown device update the BIOS
Click on drivers and downloads
Click or choose by service tag
Download the BIOS and install it on the computer
Check information after updating if same message AC adapter = unknown device; call manufaturer for a replacement AC adapter, if status has changed it is a battery problem or motherboard, contact manufacturer to test battery.
Here is your products support site: http://support.dell.com/support/downloads/driverslist.aspx?c=us&cs=04&l=en&s=bsd&os=WW1&osl=en&SystemID=INS_PNT_1501&catid=-1&impid=-1 Try to update all the drivers there is outdated. Hope this will help you.

-check the system battery information and charger information of the computer; restart the computer, while the computer is booting up, press F2 repeatedly; check "battery info"
-if it stated ac adapter = unknown device ; update the BIOS (-visit support.dell.com
-click on drivers and downloads
-click or choose by service tag
-download the BIOS and install it on the computer)
-check information after updating; if same message AC adapter = unknown device; call manufaturer for a replacement AC adapter, if status has changed it is a battery problem or motherboard, contact manufacturer to test battery

-check the system battery information and charger information of the computer; restart the computer, while the computer is booting up, press F2 repeatedly; check "battery info"
-if it stated ac adapter = unknown device ; update the BIOS (-visit support.dell.com
NOTE:other computers may have different BIOS, if it is not the same you may have to consult manufacturer
-click on drivers and downloads
-click or choose by service tag
-download the BIOS and install it on the computer)
-check information after updating; if same message AC adapter = unknown device; call manufaturer for a replacement AC adapter, if status has changed it is a battery problem or motherboard, contact manufacturer to test battery

1st try a different AC adapter. If no change, flash the BIOS, If still no change, Replace the Battery, if issue still occurs,replace the MB

you are better off getting a refund and buying a PCI wireless card and installing that instead ( linksys or netgear or something along those lines )

Are you sure your battery didn't die. Try this, take out your battery, plug in the AC adapter and power on the system. If still nothing, maybe the AC adapter has gone bad.

You need first to check if the wireless adapter is installed properly, Ricght click My computer>Properties>Hardware tab>Device manager>look for network adapter and check if the wireless adapter is listed if its there right click on it and go to properties and check the device status..

If the adapter is not showing under network adapter look for anything that says Unknown or other device and you that's where you can find a improper installed device you just need to install the driver for that.

Hope that helps........

If you right-click the "unknown" device and select Update Driver, you can force windows to search for the correct driver, and then put in the CD or floppy that came with the network adapter, and tell Windows to look on that CD or floppy. If the installation process didn't work, this might.