The machine was first booting and also working fine, after that I removed SATA cable from hard disk and reconnected back to it , now it's not coming up like no display.

I got this from isass.exe - isass - Process Information (http://www.liutilities.com/products/wintaskspro/processlibrary/isass/)

Windows errors related to isass.exe ?
Isass.exe is registered as the Optix.Pro virus which carries in it's payload, the ability to disable firewalls and local security protections, and a backdoor capability. Check that isass.exe is stable on your computer.

Recommendation for isass.exe:
DISABLE AND REMOVE isass.exe IMMEDIATELY. This process is most likely a virus or trojan. It is highly recommended to Run a Free Performance Scan to automatically optimize memory, CPU and Internet settings.

Determining whether isass.exe is a virus or a legitimate Windows process depends on the directory location it executes or runs from.

I have a suggestion on how to disable this virus:
1.)First, configure the folder options to view the hidden files to also see if the virus has a backup file.
2.)If you see a backup, uncheck 'hidden' in the Properties it if it is hidden so you can rename it(including the original virus file) and then restart your computer. It should be disabled by then.
3.)Now you can delete the virus normally.

Ooops sorry wrong send :) Anyway you could have not inserted it properly and that is why the SATA cable is not working