why can't programs be installed in my windows pc after i reformatted it?

[kittykitty]

hi! i reformatted my pc because i wanted to remove a worm (w32.rontokbro@u.mm)..but now that it's reformatted, programs can't be installed... for instance, i tried to install firefox but i get an error message that the "file is corrupted"... also, yahoo messenger was successfully installed; however, when i clicked "launch", nothing happened. i opened the control panel to see all installed programs, but yahoo messenger does not appear there...and the error still persists even when i already re-set the bios... i also switched to a new hard disk and i still get the same error... what could be wrong with my computer? which of the computer parts could be faulty? why can't programs be installed?

[weaslewise52]

You can't remove a worm, formatting. Worms reside in your memory. To get rid of the worm you have to dump the memory sticks......All of them......sucks don't it? Happened to me.