Screen goes black

My screen goes black frequently for a second, and often the screen freezes. Nothing I do (escape key, C+Alt+Delete), has any effect. Oops! there it goes again! (Rushing now before it freezes!) Then I must reset. I appear to have several out of date drivers; all devices report working properly; also, the UPS cannot be activated. Windows troubleshooter won't work; have scanned for viruses, spyware; All windows updates are current, but am unable to download drivers. Videos will no longer work with Quick Time (recently uninstalled and reinstalled). What's up, and what will go wrong next? Should I bring computer to the repair shop? Thanks for any help. Multimoe.