Hello irahul, welcome to Seven Forums...
It is NEVER safe to turn off your antivirus in order to download "hacks".. You have no way of knowing what these hacks are doing to your computer...You end up leaving your system vulnerable to whatever is waiting out there.... With that said, there are a couple of things you can do.
First, run sfc /scannow from an elevated command prompt ...
SFC /SCANNOW Command - System File Checker.. this will scan the integrity of all protected Windows 7 system files and replaces incorrect corrupted, changed, or damaged versions with the correct versions if possible.
If your problem is not resolved, do a system restore to a point before your problem started...
If your problem is still not resolved, you may need to do a repair install...
Repair Install
Let us know if you need any help, and let us know if your problem is resolved....