My iMac which I bought in 2008 shows me a blank screen when I turn it on

All I get is a blank screen. Can this be fixed or the computer beyond repair? Has anyone else experienced this? I made the mistake of downloading some pirated software which I won't do again but it seems to have totally bricked the computer. Everyone on that page said the software works perfectly but it has damaged my system or left it open to a hacker. Please any help would be good. Thanks. Basically when I switch it on all I see is a blank white screen that's it.