Whenever I start up my computer, i get the following message: ERROR 0251 system cmos checksum bad - default configuration used. press F1 to setup, F2 to resume. any ideas as to what could be causing this? i'm running it on a fairly new machine-it's barely 3 months old.

Your bios has been corupted. Hit F1 and go into setup. There should be an option to reset the bios. If that doesn't work, you may have to open your case, remove the battery or short out the bios. Look in your system manual. Once it is reset, you should be able to enter the defaults and start again. Hopefully you won't have to replace the bios or motherboard.

contact the retailer, it should still be under warranty.if they cant fix it demand a new machine.

It sounds like a ram issue. Have you added new ram? Pull out the RAM from your slots carefully (drain yourself of any static by touching on the chassis before you proceed, otherwise static will kill your RAM and the rest of the components). Check the connectors on the RAM boards and verify that they are free from any dust, dirt, oxidation and debris on the slot. Doesn't sound like it would be with a machine only a few months old. Get a can of compressed air and blow the RAM slots if necessary. Get some #2 eraser-headed pencils and scrub the RAM board conductive part lightly with the rubber eraser and clean it off with alcohol afterwards. (if necessary) Reinstall all the RAMs and do a reboot (2 times). See if the CMOS checksum error is still there. If so, either your board or your RAM or your BIOs chipset is bad.