Moving from wire to wireless

Posted this on the hardware forum but have a couple more questions,
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Dimension 8300 XP SR2
I feel this should be common but I can't find the answer anywhere and don't see it in a search of the community.
Currently my 8300 is conected to my Dell router through cable. From the cable it can access my laptop and the net. I think I know I can conect the 8300 to the router wirelessly. I have a spare Dell wireless adapter. Is it possible and can a non-expert do it fairly easily?
Actually there is an entire forum dedicated to wireless networking that you can reference IF this info isn't enough.

RESPONSE >>>
Assuming you are using a wireless router currently for your laptop, you just need to hookup the wireless adapter to your desktop, then setup encryption (assuming you are using it, which you should be). However, you should note that IF you use your network to send info back and forth between PCs that are connected via WIRE, wireless connectivity is MUCH SLOWER. This would impact the transfer of large files, such as backing up one computer to the other. Internet usage won't be affected since the internet speed your provider gives you is less than wireless gives you.
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Currently my PC connects to the router by cable - the laptop wirelessly.
Is there a written guide on how to change the PC to a wireless connection?
How much slower is wireless - opening word/excel files, copying small files.
Any possible negatives (besides speed) I should consider?