Help please pc wont boot

[hpsims]

hit there,
I wonder if any one can help, I have built my own pc which has been runing fine for the past few months. all of a sudden i installed Nero 7 & Norton systemworks 2006 & found a trojan which is deleted. Then all of a sudden my CD, DVD drives vanished & now my hard drive has too.
Now when i try to reboot my system it powers on gets me to the bios set up which recognises all cd, dvd drives & hard drives, yet when i try running from any of them even the floppy drive to reboot or reformat it wont recognise any of the drives & my system freezes.

I'm stuck now as can't see any way to access the drive to use my Windows disc to reinstall or my floppy boot disc to reinstall or even my harddrive to run off that.
Any ideas what i can do i would be greatly appreciative.
My system is as follows
2 gb corsair value ram
Athlon 64 3000= ccpu
Asus A8n-sli premium
enermax 600w power supply
akasa evo fan
300gb seagate hard drive Sata
creative 32 cd-rw
DVD drive
& seperate dvd-writeer
Other external items as well loads to mention.
thanks again

[hpsims]

Got the problems sorted to some extenet now. I reset my bios so would seem there was a problem there but still even in windows i have no access to any of my cd, dvd, drives, they say there is missing registry files, butthe drivers to install these again are on cd. How can i reinstall them or fix the registry so they can work without using the drives themselves

[mauler]

try reseting the cmos by switching the reset jumpers on the mother board. if you have already done that then if you have another computer plug the drive into that and then see what you can do. just when your resetting the cmos, make sure sure you do it how the instructions tell yo uto, i foudn that i had to leave the jumper switched for maybe 10-30 seconds on mine for it to reset