Thank god. As i had suspected it was a power supply issue (the PSU had gone) and fortunately not the motherboard. As you can imagine that was a major relief as the psu is pretty easy to replace. So im now back up and running again and can get on with some work after a nervous few days.
See what you reckon to this though.. when i took my machine into the shop to get it looked at and after mentioning my guess at the problem and the relative ease with which the problem was diagnosed and a replacement part ordered- fitted etc i then had a complete nightmare with these guys. I called to ask when i could pick it up (after numerous calls each day to check progress...) and after saying that it was ready to be picked up- it was then dropped into conversation that 'i noticed you only had this type of anti-virus and as a business client we have installed sympatec (norton av) on your machine....' at which point i stopped really hearing what was being said as my eyes and ears started pouring blood.
Needless to say i wasnt happy and tried to make this clear, politely as possible- stopping short of name calling and told him to take it off and i would be there asap. When i got there (fortunately a few mins drive away) my machine was waiting to be picked up- and had only just been unplugged. Heres the problem with this as i see it. You have to trust these people with your machine that basically has your life on it- everything from my company information to family videos and photos, if i bring a machine in that has a hardware issue i do not expect to be told that they have been 'looking through your machine'. The OS, software, files etc are all off limits as far as im concerned, the only time they should even have had it on was to check that it booted and then shut it straight off again.
Telling me that they 'always perform a checklist of stuff including security checks etc etc' does not justify this intrusion especially if i was not made aware of what they were planning on doing when i dropped it off!
To top it all off i obviously ended up having to pay through the nose for the part and then their time to put it in- and i was even going to be charged for them dicking about with my OS! (after mentioning the 'misunderstanding' this additional charge was dropped)
Anyway- after getting everything home, and checking everything out, all seems well but if i can ever help it i wont be taking my machine anywhere ever again!
/end rant - back to work.