"you need permission to perform this action- try again or cancel"

hello geeks

I have a dell vostro 1510 with Vista 32 home edition
not sure if this is the right category but I am stuck with this problem so posting here. i am trying to copy files from C deive to external usb hdd but I get this message - "you need permission to perform this action- try again or cancel button" after the normal vista uac continue messages

it just doesnt alow me to copy files or create new folders. I can use the same usb hdd on other laptop with XP and no problems. After lot of googling i could not fix it..
this was working fine till last week not sure what happened

hoping to get some advice.

thanks

rj

Do you have a restore point dated before the errors started?

unfortunately not

You could have picked something up. I would try this
http://www.vistax64.com/system-secu...-pc-clean-remove-malware-four-easy-steps.html