10.6.8 "infected"?

Question

Been using 10.6.8 for years, no problems. Recently I'm seeing the Beachball soon after start-up, nothing shows in Force Quit window, suspicious Anonymous Process (need to note PID) comment after doing a Forced Shutdown then Reboot out of Single-user Filecheck.
If I check Activity Monitor at start-up I see a MDS function with a large CPU %. Trying to do an Inspect gives me password window then Beachball.
Did a DiskWarrior directory rebuild not too long ago, and Permissions verify thru Disk Utility running off another, maintenance hard drive.
I'm wondering if somehow I have a compromised OS now that Macs have become so much more popular with all the iPhones & iPads out there, to say nothing of actual computers....
Where the heck do I begin to look for suspicious activities / files / processes?

Answer 1

Thanks Lanny, that's a comfort knowing MDS isn't malicious.
Spotlight's never seemed to cause the "beachball" before so I doubt that's the cause of what I'm seeing.
Running FSCK a couple more times seems to have improved things markedly.
Also found thread(s) re: Flashback trojan with Terminal commands given which gave "no such item" as result so there's comfort in that also.
Still, will try to become more adept at ferreting out current threats & whether present....