It may be much older. But in short the first thing I'd do is this (read link, follow directions)
It's possible they (and us) need to know what you are doing when you see this happen. We know about the FLASH issue and advise to turn off FLASH HARDWARE ACCELERATION to avoid that common issue but now you have to tell more story. What are you doing when it blacks out?
My picture just goes blank, all I get is a black picture and to get it back, I have to turn off the processor then switch on again. My PC is three years old and Insured with Comet, recently I had the graphics updated and the PC cleaned by Comet, when I got it back, the problem started. Comet say that they can't find anything wrong with it and they only have my word that there is a problem, It is Insured for five years with two to go.
Operating System: Windows Vista™ Home Premium (6.0, Build 6002) Service Pack 2 (6002.vistasp2_gdr.111025-0338)
Language: English (Regional Setting: English)
System Manufacturer: HP-Pavilion
System Model: FZ122AA-ABU a6635uk
BIOS: BIOS Date: 06/23/08 16:36:25 Ver: 5.24
Processor: AMD Phenom(tm) 8550 Triple-Core Processor (3 CPUs), ~2.2GHz
Memory: 3582MB RAM
Page File: 1143MB used, 6239MB available
Windows Dir: C:\Windows
DirectX Version: DirectX 11
Comet wants £30 pounds to look at it againg because the picture never blacks out when they have it?