iMac not working after trying to re-install snow leopard

hi - have been having massive problems on my imac.

my imac was running on the latest lion OS and then installed the icloud update. i think this update made my machine super slow and so i tried re-installing snow leopard but that didn't work and now my machine is stuck on the grey page with the apple logo.

tried the safe boot (holding down the shift key) and unplugging everything and that didn't seem to work.

any and all suggestions would be great - thanks!

imac version - 2009 version 27"

You should be able to reinstall and run Snow Leopard on that iMac. How are you trying to reinstall it? Are you booting the machine with the Snow Leopard DVD? Tell us exactly what you've attempted to do to install.

i rebooted the machine w/ the snow leopard install disc in the machine and the imac hangs at the apple icon screen and never boots to the disc. i've even rebooted and held the shift key down and it still hangs on that screen.

the only way i can do anything is hold the option key down and boot to the recovery hd and then am stuck.

Are you sure you're using the correct Snow Leopard DVD? It either has to be the retail version or one that specifically was included with your 2009 iMac.

When you say you re-booted- was it trying to boot to the CD, or had you managed to do a re-install? Have you done an SMC firmware update on the Mac (updated the mac from with the Built in updater? ). I'd suggest using the recovery HD and thn running a permissions repair on the drive. This usually fixes the speed issue as incorrect permissions are usually the corrupting factor that slow macs down. You can also do an HD repair from there. However, if you've done an SMC update, your original OS installer may be incompatible with your mac.