If this is a custom built PC thats still under warranty then contact the supplier before doing anything else.
If it's one you've assembled, why do you need to get into the BIOS - have you changed the default from Auto with regard to which video output is used (onboard vs discrete card)? If so, you can reset it to default BIOS values by unplugging the PC (incl monitor) from the mains and removing the coin cell battery from the motherboard for 30 mins (at the same time remove the graphics card from the PCIe slot). If the motherboard battery has been contaminated with coolant, they're cheap enough to replace rather than trying to clean it. When the PC is powered up again after refitting or replacing the battery, all BIOS settings (such as date/time and hard disk setup etc) should be at default values (which means Auto for whether to use onboard or discrete graphics) so you should be able to get into BIOS setup then.
Before using the PC again though, the first thing I'd do is to take the PC apart and carefully inspect everything for signs of damage or contamination. Source some contact cleaner (specifically developed for cleaning printed circuit boards with components on them) or IPA (Iso-propyl-alcohol) and an old toothbrush and give all the affected components a good (but gentle) clean. The last thing you want is coolant drying on components such as the motherboard.
Are you going to retain the water cooling system or replace it with the standard fan arrangement? My DG45ID is fan cooled and it's a very quiet system so this is possible to achieve - especially so because it's not possible to overclock with a DG45ID and therefore there's no need for the 'heavy duty' cooling capability water cooling systems are capable of.
Thank you for your response.
My machine is a custom built machine that I put together about a year and a half ago. I'm almost certain that the after market video card that I installed is pooched.
The reason I need a CPU cooler is because I watch alot of downloaded movies through my PS3. When I used the stock intel fan it wouldn't cool the CPU fast enough and the computer would shut down due to excesive heat; almost 100 degrees Celcius!
As I just started the work day, I won't be able to try your solution (which I am sure is THE solution) until later in the day...I will keep you informed.
I appreciate the feedback!
Thank you again.
What CPU and case is your computer built with and what format were the troublesome media files in (and what playback resolution)? I very rarely even hear the CPU fan speed up from the default 1125 RPMs on my E8500 even when taxed with Blu-Ray or HD-DVD playback so I wonder why yours is struggling. Is there plenty of air flow provided by the case fan(s)? I have 2 case fans as well as the PSU fan, 2 of which are 120 mm and 1 is 140 mm and the case fans operate very quietly around 600 RPMs - I imagine the PSU fan is similar.
As far as media playback is concerned, the GMA X4500HD (built in graphics chip) perfoms OK and it's things like demanding games or graphic manipulation / design software that it may struggle with. If your CPU was overheating just when playing back media I wonder if something else was going wrong there. If you have loads of software and plugins loaded onto the system, maybe a clean install (using the latest Intel drivers - with the exception being the audio drivers if you use the optical/TOSLINK port for sound - windows own drivers won't cause lockups) would make a world of difference.