1. Yes
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Live CD for removing malware?»
Best free bootable antivirus for usb stick?2. yes, most of the time, but it is always better to check with a couple of different programs
If you have a locked down computer spare with an A/V, using the infected HDD as a slave and scanning will also work.
3. See point 1 and also this »
Security Cleanup FAQ »
Rootkit Detection ApplicationsNote: if anything is detected, to be safe, visit »
Security Cleanup