"No Signal" Monitor controls?

Box in the centre saying "No Signal" with R/G/B coloured boxes underneath. OS XP-SP3 and Flatscreen is GEForce 6100, Gateway HD2200
Recent History today: I was removing Canon (picture editing) programs that hadn't been used since 2006, and changed my Firewall from Outpost to Online Armour. After Restart i have this "No Signal" small coloured window.
Monitor On/Off Touch Menu at the side of the monitor is royal blue and no able to change any settings for video and resolution.
I opened NVidia to try the Optimize Wizard, but couldn't find any 'controls' they referred too, to adjust any colours/brightness etc...
My Recovery Discs are at the local computer store, so unable to recover those till next week? Thank you for ur help - i am a novice; so instructions need to be detailed. Sue Hart

 

What happens when you start in safe mode?

 

Plodr - i restarted and chose safe mode, the monitor control menu responded immediately asking for settings.. i was able to set and now that 'box' is no longer active.
Thank you so much, never even considered trying safe mode.
Sue Hart Edmonton, AB, Canada