My laptop monitor blinks repeatedly. Running XP. Had new hard drive installed a few months ago. Unhappy with computer repair guy who did work. In addition to this problem, I have had the computer just shut down while browsing the web. Have checked all cables connecting. Everthing snug. Any ideas?

Hi there and welcome to PCHF, can you boot into Windows and navigate to C:\WINDOWS\minidump, and upload the BSOD logs if there are any present. One of our tech team will then look at them for you.