Monitor suddenly not being recognized (low resolution)

[davidar]

I have a ASUS S775 P5S800-VM motherboard with an onboard SiS 661FX graphics card, and a BenQ FP71G LCD monitor with a native resolution of 1280x1024.

When I turned on the machine yesterday morning, however, the maximum screen resolution had dropped since the night before. This is the case on both my Kubuntu (maximum resolution of 800x600) and Windows XP (1024x768) partitions, so I'm assuming it isn't an OS issue. The monitor seems to be being recognized as "Default Monitor" now, rather than "BenQ FP71G" as it had been previously - XP even had to install a driver for Default Monitor when it started up.

I've also checked the monitor with another machine and it works fine, so that isn't the issue. So the only potential issues I can see that are left are the BIOS or the video card itself. The BIOS has a habit of randomly changing settings by itself occasionally (I have no idea why), so I'm hoping that's what the problem is. I've tried googling various BIOS options for video related issues, but none of them have worked so far.

So my question is, what could the problem possibly be, and how could I go about fixing it?

 

[Smartsync]

does your BIOS keep changing to random settings or default settings?
if it keeps going to default then maybe your battery or CLR CMOS Jumper has gone dodgey.
have you tried uninstalling the driver for the monitor and restarting the system?

 

[davidar]

does your BIOS keep changing to random settings or default settings?
if it keeps going to default then maybe your battery or CLR CMOS Jumper has gone dodgey.

Come to think about it, it probably is the default settings. I'll have to have a look at those to see if there's a problem. However, I guess this means that the BIOS isn't causing my current problem (as I haven't had this issue when it's reset itself before)?

have you tried uninstalling the driver for the monitor and restarting the system?

No - as it affected both OSs simultaneously I don't see how it could be a driver issue, and even if this did fix the problem for Windows I'd still have the problem with Linux.