Very wierd refresh problem!

Few weeks ago I left my computer on and came back to a thoroughly on fire monitor. :(

I got it replaced but I noticed with both the temporary interim monitor I used and my new replacement monitor, that I have to turn the monitor on with the PC. If I don't and turn it on once Windows has loaded then the monitor complains of "out of range" every time.

My refresh is only 75Hz @ 1024x768 so isn't extreme for the monitor.

Could my GC be the cause?

so i take it runs fine in safemode etc (defult res + defult refresh rate) i could suggest you reload your gc drivers and if you can find any your monitor drivers, if not set it up as a plug and play monitor reset a couple of times and see how it goes.