Cant load anything, no usb osx install, cd or anything

So I have an iMac late 2008 core 2 duo 6GBram 500GB HDD, Right after 10.10.5 update it froze while watching Netflix and I had to force a restart and my mac started the awesome boot loop. So I tried safe mode, recover, single user and even verbose mode to see what was going on, It starts up and then about 40%into boot it would just restart. If I try to boot from the install usb I made (Which I know is good and used every day at work [I'm a computer consultant] it will load for a min and then I will hear "To use English for the main language press the return key But it will still show the loading symbol and apple logo (which is frozen right before I hear the mac speak) If I let it set for a few mins the screen will go black (even though its still on [kinda like it went to sleep]) but if I move the mouse it wakes up (hardware wise) but the screen remains black. I pulled my HDD and tested it and there is nothing wrong with it what so ever. I deleted everything off of the HDD thinking it was just hung up. Now I have a blank HDD that I cant even load the osx install media to even do anything. Ive tried searching and searching and I can not find anything, and the general troubleshooting steps is not working. I'm completely lost and have no clue what to do now. oh BTW when in verbose mode the last thing that would load (before I cleared the HDD) was was:

NVDAStartup: Offical

NVDANV50HAL loaded and registered

right after that line and before the next one appeared, that's where it would restart, Almost every time.

Thanks in advance

-Paul