Uh...okay.
First of all: Any error messages? If you've seen any, copy down the text or transcribe it and post it here.
Next: While waiting for a response to the additional information, look into finding generalized solutions via a search engine. See if it is a problem with virus protection (real time scanning, most likely) or some other permissions based system. Are you logged into your computer as the administrator? Did you install under that account? Also check to see if your drivers are fully up to date.