Really need your help guys...

[progbuddy]

It might be a problem more with the southbridge than the northbridge if you overclock. Try finding a bigger northbridge, and if your southbridge will accept a heatsink, try a bigger one for that. Also, a problem I have experienced happened with people "accidentally" putting magnets next to harddrives. If you have another harddrive with an OS on it, try booting from that HDD.

[monoflap]

Having to replace the reservoir and whatnot over the past 2 weeks has left me with a PC that crashes during start-up...

Why did you have to replace the res? Because, If you ran the comp with out the water cooling functioning properly chances are you damaged your hardware perhaps even killed it .

[slytherock]

One of the first reason of the blue screen of death corrupt driver. Use driver cleaner and reinstall your drivers first

As mentionned, it could be a heat problem. But if you're watercooled, you're probably also OClocked. If yes, other things can be in cause:

First what's your temps?
If your temps are acceptable:

1: Too much oc on the cpu
2: Your ram dont support that much

It also can be a faulty part:

1: try to downclock
2: Use one stick of ram at a time