Being the administrator of your computer gives you limitless access and control, but is it a good thing?
Let me make this completely clear:
It is not good.
The reason is the overwhelming majority (somewhere around 90%) of malware, viruses, and other exploits can only take hold of your computer if you are logged in as the administrator.
Don’t get me wrong, I’m not suggesting that you shouldn’t have admin rights on your own computer. What I am suggesting is that you password protect your admin account, and only access it when you need to install software or make a change to your system.
For the everyday stuff, make yourself a regular user account. It could save you a ton of hassles.
Practice safe computing.
The Geek Whisperer 
Great tip D. I’ll follow it.
This actually only applies to Windows XP.. in Windows Vista and 7 even if you are an Administrator, you have UAC which prompt before installs and system file changes like on a Mac.
Jason, I have to disagree with you this time:
http://www.informationweek.com/news/windows/security/229401694
http://www.tomshardware.com/news/windows-windows-7-uac-malware-malware,10054.html
http://www.techworld.com.au/article/383052/admin_rights_underpin_many_windows_exploits_analysis_finds/
Regardless, that UAC also assumes that the user understands what change they are accepting.
David – those first two articles seem to assume UAC is turned off (as most users turn it off cause its annoying). The third one actually says to use UAC and be willing to click no.