How do I make my Dell Optiplex SX280 wireless?

The Chromebook has a wireless network interface.
So, it does not connect to your computer.
Instead, it connects to your wireless router.
If you do not remember that password for your wireless network,
you need to "reset" your router to its "factory-settings", and then recreate the name of your wireless network, and enter a new password, to define it.

For Windows XP drivers, the last supported through Dell, try one of the three listed here:
http://www.dell.com/support/drivers/us/en/19/product/optiplex-sx280

Change the Operating System to "MS Windows XP" and the Category to "Video".

This discussion suggests that Windows Update will get you working drivers after a Windows 7 install:
http://en.community.dell.com/support-forums/peripherals/f/3529/p/19329672/19807012.aspx

If you tried to install a BIOS up-grade and it failed, then your motherboard is toast.

Get a VGA converter adapter plug.

Desktop computers do not usually have a wireless card installed. They will have a built-in LAN card that uses a LAN cable.
If you want to connect your computer using a wireless connection then you will need to install a wireless card in your computer and configure it to communicate with your wireless router.
Otherwise you can connect to your wireless router using a LAN cable.
Your wireless router may have built-in LAN ports and you can connect your computer to the wireless router using a network cable.

Yes it will. Please check Dell OptiPlex SX280 specs here. It supports Serial ATA hard drive.

If your hard drive has failed a) you need a new one, b) you will have to reinstall the Windows system but c) you will have lost anything you stored on the computer. This is why we encourage people to have backup systems.

check ur battery dude.....ur battery life must have gone!!!!!!

Your computer uses what Dell calls a "Module Bay". Instructions for removing devices from the module bay are located here.

http://support.dell.com/support/edocs/systems/opsx280/en/ug/mod.htm

If this answers your question, I'd appreciate a FixYa rating!

Good luck!

What you need is some access-point devices, buy one or two depending how far away it is, set them up,,,and you will be fine

Good luck
Nic