Clean Installation of OSX

Hi Friends,

I am in serious trouble and request the help from the best of the OS X technologist out there.

Problem is my OS-X (10.3.3) got virus effected (Its true, even though some of you might raise their eyebrows at that line). Here is the behavior of the machine.

1> Its automatically types, and all the typing happens in CAP's even though I tried all possibilities of deactivating the caps' lock. SystemPref etc.

2> System goes super slow, like each finder takes at least of 5-8 sec to complete its animation to max / minimize its window.

So, I decided to format the system (clean install), went to utility and tried almost all version of OS-X available with me (from SL onwards). Although it troubled me to initialize the partition due to "disk unmounting issue" first , yet using USB , was able to flash the OS in it. However, to my surprise, even after doing 7 secure formatting and partitioning and flashing , it appears the system behavior has't changed. It is to an extend that in order to register the OS-X , I can't type my name and password because of this auto typing stuffs. So, any of you can please help me regarding this as I am stuck.

This is how I solved this same virus in Windows. I got same virus in my another Lappy with windows as well. For that even after reformatting and all things were not changing for a long while. After hours and days of hunting, I found windows, had a small 10MB SYSTEM folder, which is where their core stuffs were there. Every time, we format, we won't get this SYSTEM partition get formatted and this virus had effected this one. After a lot of hassle, I got a way around to wipe this SYSTEM and was able to irradiate this bug in Windows and is working fine from past few weeks.

I am core engineer but with MAC, I haven't exposed to SYSTEM level and wonder the issue lies in some filesystem which is infected but not able to reach while formatting and hope, someone could really help me figure this out.