iMac 27" a1312 not booting after dust removal

I please need your support. ..

There are eleven A1312 machines. Some have known issues, Please identify which one you have: http://www.everymac.com/ultimate-mac-loo...

Did you change anything, like the hard drive? Did you replace the thermal paste? What system are you running? Was it booting before you started your repair? Did you recently do a system update? Will it boot from an external or from your recovery partition? Do you have another Mac you boot into Target Mode with? Do you have an original system installation optical disk? Do you have virus protection? Do you have a Time Machine backup drive? Do you have any type of external boot drive?

Dear @mayer

I will check which of the 11 imacs listed is mine tomorrow since it is in my lab now .

The imac was fully functional but shutting down after a while because of the dust so i cleaned its interior and changed the thermal paste over the graphic card and the cpu.

I had replaced its hard drive a year ago with an SSD hard disk and installed Windows 7 , noting that everything was totally functional until the dust removal.

I tried to disassemble the whole imac and reassemble it twice with no changes .

I even removed the RAM and i am still getting the same result ,

A fan spinning and mouse led blinking for 2 seconds then it stops and every 5 seconds the same thing happens over again, i didn't try any bootable drives or backups since the imac is not booting at all .

I anticipate a hard drive heat sensor issue,

@mayer

The ssd hard drive is not supported by the imac sensor wirei cannot plug the imac's sensor in it but it was perfectly working before cleaning the dust ...