Windows 7: Windows Explorer malfunctioning on admin account

I need some help on this, i'm going nuts here! First time on the forum, if any other information needed please ask, there's probably loads i've missed out.
This may have been going on for longer than a week or two, but that was when I first noticed it. The only program I can think of that i installed recently is google earth.
I have a Compaq Presario CQ61.

After logging on to main account, explorer takes around 5 minutes or more to load fully.
Installing programs doesn't complete - after first fade screen to "do you want to allow this program to make changes" and clicking yes, computer hangs at faded screen before exiting and continuing as if pressed no.
Opening start menu sometimes causes computer to hang with rotating cursor, becoming unresponsive.
Trying to run system tools like cleanup, system restore and resource monitor can take a long time to load.



I've ran scannow and dskchk, and without being an expert there wasn't anything that jumped at out at me as saying "error". Still have the information here if needed.
Restored system, no effect.
Ran system in safe mode with networking to download mbam, downloaded but still could not install. Did however manage to update adobe flash player, which was previously impossible.

Created new user account with admin privileges, everything works perfectly - installing, running system tools, start menu, and log on all run as normal, but back to main account and same problems still remain.
Ran mbam in new account, no problem files found.