If i install Windows Defender, can or should also install other anti virus programs such Sy Sweeper or AVG?

johnnybello;

It would be unwise not to also install an anti-virus. Windows Defender is an anti-Spyware and is not concerned with Virus infections at all. Microsofts home user Security applications are shown graphically here:

Ms Security Applications

No single product is 100% foolproof and can detect and remove all threats at any given time. The security community is in a constant state of change as new infections appear. Each vendor has its own definition of what constitutes malware and scanning your computer using different criteria will yield different results. The fact that each program has its own definition files means that some malware may be picked up by one that could be missed by another. Thus, a multi-layered defense using several anti-spyware products (including an effective firewall) to supplement your anti-virus combined with common sense and safe surfing habits provides the most complete protection.

My windows update downloaded this program but where do I find it and what does it do????? Mostly, when does it scan and where are the results???? I really hate having to be my own IT guy.

Defender installs in C:\Program Files\Windows Defender\MSASCui.exe

"Windows Defender Overview"
"Release Notes"
"Windows Defender FAQs"

"How does Windows Defender work?"
"How Windows Defender identifies spyware"
"Windows Defender antispyware cycle"

Note: Defender has an advanced option to use heuristics to detect potentially harmful or unwanted behavior by software that has not been analyzed for risks. Heuristics allows Defender to detect potentially malicious activities for files that are not included in its malware definitions. The disadvantage to this feature is that it can potentially increase the chances that a non-malicious program is flagged as malicious. With heuristics, there is always a potential risk for a "False Positive" when the heuristic analysis flags a file as suspicious or infected that contains no malware.

"How to scan for spyware using Windows Defender"
"How to Schedule when Windows Defender scans your computer"
"How to use Windows Defender Software Explorer"

Undeniably true, and yet interestingly, I've been using Defender all the way through its beta phase up to the present and it has never registered a single false positive response on my computer. (Actually, it's never found anything at all, but that's another story!) Although it doesn't have a good reputation for detecting malware as a scanner, I keep it on board because of its option to report significant system changes, which option I always keep switched on. (Yes, I know there are alternative programs that do this, but I feel comfortable with Defender after all this time.)

Yes you can download other anti-... once it helped me to remove spyware and blocked harmful changes made by spyware