It does sound like a bad connection, check cables and connections at both the PC and monitor ends. Could be caps in the monitor going bad (as mentioned above) but it could also be your video card crapping out. You might not know until it is too late. If you have an extra monitor and/or cable, hook them up to narrow it down to JUST the monitor having issues.

__________________
TC
Current stable:
- 2004 Mazda RALLYWANKEL
- 2007 Saturn sky redline
- 2004 Explorer...under surgery.

Past: 135i, GTI, 300E, 300SD, 300SD, Stealth