when pc is put on, i get the message
'the CPU is unworkable or has been cahnged'

pc is 1 year old and this message came up when i first put the components together but stopped coming up. and now its started again...on every startup the message comes and and it says press F1 to continue, then windows loads up just fine..also when computer comes out of sleep mode i get the blue screen of death, this has been coming up since the beginning when pc was made...

Intel core 2 duo E6600
Abit Fatality P190

When you built the machine, did you install windows vista or did the hard drive already have vista installed on it. If so, it may be that vista is stuggling with the hardware changes, try reinstalling from scratch.

When you are asked to press F1, does it also give you the chance to go into the BIOS/Setup?

If so, go into it (usually by pressing F2 or Delete key) and exit saving settings (usually by pressing F10).
After this, does it still complain about CPU? If not this means that BIOS detected a change and wanted you to confirm it.

Also, the bluescreen of death could indicate a memory problem, to check, go to control panel, click classic view, double click administrative tools, double click Memory Diagnostic Tool and choose to restart now to check for problems.

If it detects a problem you may need a new stick of RAM, remember when installing memory chips to earth yourself to discharge any static electricity that may have built up in you as this may damage the chips.

Don't forget to update us on how problem is going so we can learn from it.