There are just way too many choices available to provide a simple answer. I would recommend more searching just to see what's available.

There are cards for desktop PCs that allow for typically 4 camera inputs and hard drive recording. Software can be tricky and may not offer as much flexibility as wanted. You are also going to be using quite a bit of power running a PC 24/7, won't have web access to the cameras, and it usually doesn't reboot to the program after a power fail.

There are several stand alone systems available, but with mostly all of them from China, they all seem to have a few quirks and some can be frustrating to setup. That said, however, some of the more popular brands in this market have been getting better - read some of the online buyer reviews.

For best image quality stick with CCD sensors (instead of CMOS), built-in IR illumination for night viewing, choose a camera with the proper field of view, and stay way far away from wireless cameras.

Thank you for your reply. Computer wise I had forgotten to consider reboots and such. That eliminates the salvage computer approach.
I do read reviews. This is what first attracted me to Newegg and Amazon. The more I read the security ones it seems they all have problems but I have read reviews for years I get it all sorted (I hope).
Looks like my big weakness is my lack of knowledge in cameras. Install knowledge is good on my part and I kind of figured the ease of a wireless camera was too good to be true / trusted. I need to figuring my exact camera placement and focal length. I like to cover the city street and sidewalk with one. We live in a pretty old neighborhood downtown lots are 50 foot wide low flow traffic street even lower sidewalk traffic.
In my neighborhood the general break-in starts with knocking on the front door if not answered they break-in from the back. The preferred house that has an alley (most all do I am lucky and don't) they put the stuff in the trash area and pick it up as if they are aluminum pickers using some type of vehicle or they load your suitcase with a haul and escape on the city bus. Thanks again for taking the time to reply I learned a great bit.

A couple other websites you may wish view to give you ideas of products are Costco.com and Samsclub.com - look under electronics and then security/surveillance.

Also, if you Google "cctv field of view calculator" you'll get some websites where you can plug-in distances to get ideas of the type of lens you may need. You'll want to find the ones that offer 1/4 inch sensor size as that is the most common in consumer systems.

If you sketch out you home and property to scale, measure distances, decide on areas of coverage indoors & out, it'll give you a better idea of what you may need. It also let's you figure cable lengths for each camera since many come with pre-fab cables of 60' or so.

Everybody's needs are different. We live up in the Sierra mountains with a fair amount of property and I'm more concerned with being able to see wild fires in summer or trees falling in winter storms, when away from home. When we lived in the city, it was about watching the doors and windows around the house.

What ever you buy spend a few extra bucks and buy a system that has a good warranty. Most cheap kits you can buy at a retail store have a 1 year warranty. And they end up lasting a year too! Buy something that will last. Plus what is the point if the cameras are so cheap you can not even see the persons face when they walk by your camera. You never know when the video you are recording will come in handy!