Windows 7: W7 64 problem

Every time I start Windows 7, I must re-enable Windows security center to run it. And every time I connect my camera (canon G15 or Nikon P300) I must re-install the driver to download my pictures. Can someone help me? Thanks.

Is this the original factory preinstall, or have you gotten the superior Clean Reinstall - Factory OEM Windows 7? If retail have you gotten close to the perfect install described in tutorial?

If so work through these Troubleshooting Steps for Windows 7

It is the original factory preinstall, and it worked for several months...

can you show us how you enable the Windows security center?

about your cannon drivers. if you connect them with usb cable, why would you install their drivers?

have you installed any additional programs to clean your computer on restarting or cleaning your registry?

Trust me, Windows security center is enabled as it should.

When I connect the camera, the computer gives a beep, but the G15 is not showed in the drive list (as usb station). It is only showed under Devices and Printers with an exclamation mark. Then I must click on Troubleshooting and Windows reinstalls the driver and all things work.

I have installed Kingsoft pc doctor and Ccleaner...

Any "PC doctor"-type optimizing crapware will likely ruin your Windows 7. It's even worse than running the corrupt factory preinstall which no tech enthusiast would do.

What you want is a perfect install which will stay that way if you only use the tools and methods given in Clean Reinstall - Factory OEM Windows 7

then uninstall them and see if the problem is gone?
most times these softwares conflict with other settings. i dont recomend them until its necessary.

Uninstalling might not be enough if the crapware was used to tweak system settings that are now corrupted. I would see if you have a System Restore point to get back before the "PC Doctor" was installed. If not uninstall it and run SFC /SCANNOW Command

It must be Ccleaner or AVG 2013 virusscanner (I think).
what is your guess?
I will disable both and then run SFC/Scannow.

BTW... thanks everybody for your help!

I was referring to Kingsoft Software Doctor reg cleaner and tweaking suite you mentioned. These are all trouble for Windows 7, except CCleaner which is always safe. I would restore before you tweaked with Kingsoft, or at least uninstall it if restore point isn't available.

AVG also can cause problems and is not preferred by anyone here since it bloated up and never slimmed back down. I would uninstall it and replace with Microsoft Security Essentials.

Work through the other Troubleshooting Steps for Windows 7 to check it over good.

I asked you if you have an original factory preinstall which no tech enthusiast would run to begin with?