Microsoft's Anti-Spyware B1

Anybody else have odd issues with MS's Anti-Spyware? I've felt it's been dragging down system performance, so I've been trying to run with it disabled in order to get some subjective comparisons. Right-click on the taskbar icon, select "Shutdown". A dialog appears with dire warnings that my system will be suceptible to spyware attacks and may even do something more horrific. [What, like register itself as a Howard Dean supporter? -- ed.] Fine. Click "Yes" to confirm that I know what I'm doing (supposedly). The little icon goes away and everything looks fine and runs just ducky. Until... Some hours later, I notice Anti-Spyware's icon is back in the taskbar. Hmmm... I had no notification it was starting back up, nor can I find any preferences or options which would explain to me why this is happening. This has happened several times on both of my systems. Software that starts up on its own and sucks up resources even when you've told it to stay gone. Wouldn't that be considered, well, SPYWARE??? I need to caveat this with the note that I've not done much checking into MSAS's configuration, nor have I even looked to see if there's an online forum or blog where I can go for more info on it. What, you want me to actually do some research before ranting? Hah!