I am running Window Vista Home Premium (with SP2) with automatic updates on my Compaq SR5606UK Desktop PC with an AMD Athlon 64 X2 Dual Core processor 5000+ 2.60GHz with 3.00GB RAM & 32-bit operating system.

Recently I'm getting an intermittent problem at start-up. Windows is loading normally to the desktop stage and certain icons are loading into the system tray (eg. clock, network , safely remove etc) but then everything freezes and the only option is to switch off, either at the mains or by holding the on/off switch on the PC case. Sometimes this happens several times before a successful start-up is achieved. Other times, a normal start-up happens straight away. I've run diagnostic checks and everything reports as OK/passed. I've also run AVG virus checker and nothing is found. I did run a Microsoft System Restore which seemed to resolve the issue for a short time but as the problem is intermittent that may have just been a coincidence. Any suggestions, please.