[Nick2009]

I shut down my computer earlier today; rebooted it in the evening but it would not load. Instead it simply cycled through a series of constant reboots each anything from 2-10 seconds apart.

My monitor will not find an input from the sapphire hd4850 it is connected to and the sapphire hd4850 displayed a flickering red led of 'd1601: over-heat protect straight from startup and this will continue till the forced reboot and then start over.

I googled the issue, which seems to be very popular for the hd4850 range and tried some of the suggestions, which included:

- resetting cmos
- removing gfx card and re-attaching it.
- unplugging and unattaching everything apart from the graphics card and the power supply to both the graphics card and the cpu.

The last suggestion caused the reboots to stop (which initially makes me think it is a power issue - but I do run a 550w coolmaster psu, which is only 13 months old) and the flicking red led of 'd1601' to instead become a constant red led of 'd1601.' However, the monitor still does not work and the constant red led remains even when the monitor is not attached to the gfx card.

I run a Gigabye GA-DS45 motherboard, coolmaster 550w psu unit, sapphire hd4850 512mb, 4gb corsair ram and d2c processor.

I have had no problems with the computer for 13 months and definitely no heating problems (the inside has 4 fans including the gfx fan) and I do not overclock. BUT upon moving, 2 months ago I have noticed small problems with the machine, such as the monitor crashing, requiring a reboot and the monitor lead to the gfx card being a little sensitive in order to work.

I do not have access to spares to swap and test each part. So, in many respects, I'm at the stage where I guess it could be any part of the computer. I'm assuming by the red led light remaining when the monitor isn't attached that it isn't the monitor. All the crap like the keyboard & mouse aren't attached either.

I guess in reality it comes down to 3 areas: motherboard, graphics card or psu. I haven't removed & reattached anything BUT the gfx card and the leads in the motherboard.

Help & advice greatly appreciated!