An older (~3 year old) PC I have passed on to my younger brother has a Sony 17" LCD monitor and uses on-board Intel GMA 3100 graphics (supports Aero under Windows 7 and no more is required). Recently he has complained to me twice that after booting up the screen looks all 'fuzzy'. Initially I thought maybe he messed up the ClearType settings by mistake, but resetting that did nothing. The only thing that finally worked was changing the resolution to something else temporarily, then setting it back to the original native (highest supported) resolution. The second time this happened the same 'fix' worked.
This is happening only intermittently as of now and is not predictable/reproducible. I suspect either the monitor or on-board graphics is dying.
How can I check and confirm which of the two it is (or maybe something else you guys can think of)?
If it's the on-board graphics, would I be able to keep using the same motherboard with the addition of a cheap PCI-E graphics card?