Cant install new os

Would you be able to put the HD in another system as a slave drive & format it then???

Make a rescue disk on a good system, boot it up on the suspect system, 1st, back up your files to USB sticks, then disinfect the pc if possible. If not, you'll need to start fresh.

http://www.sysresccd.org/Main_Page

http://www.free-av.com/en/tools/12/avira_antivir_rescue...

im going to try to format my hd on another computher and see if that works i will let you know

how do i figure out witch of my two hard drives is my C drive they are both the same HD and i put them both in when i built it so how do i know witch is witch

Usually the Windows folder that has a later modified date & time. What OS is it? What is on both drives?

im using vista 64 and on the c drive is my windows and on the d drive are all my family pics and movies and some games. the only thing is i can get this comp to boot so i was going to take out my c drive and format it using another comp the reinstall windows

Ok, find Windows folder on both drive. The one that has it is the OS drive.

If the harddrives are ide's(wide flat cables with 20 pins) the jumpers on the back will say master,slave, or cable select. If cable select, the first plug(black) is the master,c, grey is the slave. SATA drives, I am not sure, but if the jumpers on the back of the drive are set to cable select i think sata1 is C drive.

For future reference, I always notate which drive my OS is installed on. If you look at the drives in your BIOS, you can see that they have unique identifiers. I also make a note on the HDD itself with a sharpie. Redundant? Yes, but I'd rather be safe that sorry. I've been in your shoes one too many times. That might help you in your future troubleshooting though. Best of luck to you!  

thank you all for your help i am going to make what is what when i get this all figured out and yes they are sata