Blank Picture 2

by superman41 - 4/2/12 12:30 PM

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?

Any ideas?