kwgammie, start of by performing what Apple suggest:"
Simply performing a Safe Boot may resolve this issue.
Shut down your Mac. If necessary, hold your Mac's power button for several seconds to force it to power down.
Start your Mac, then immediately hold the Shift key. This performs a Safe Boot. Advanced tip: If you want to see the status of a Safe Boot as it progresses, you can hold Shift-Command-V during start up (instead of just Shift).
Note: A Safe Boot takes longer than a typical start up because it includes a disk check and other operations.
If your Mac starts up as expected, immediately try restarting.
If the Safe Boot does not work, or the restart after a successful Safe Boot does not work, go to the next section.
Reset the NVRAM / PRAM
Shut down your Mac. If necessary, hold your Mac's power button for several seconds to force it to power down.
Reset the NVRAM / PRAM.
If the gray screen issue persists, go to the next section.
Start from your Mac OS X Install disc; use Disk Utility
Insert your Mac OS X 10.4 or 10.5 installation disc (if you have discs with both versions, use whichever is closest to the Mac OS X version installed on your Mac; do not use a startup disc which came with a different Mac or which contains an earlier version of Mac OS X).
Shut down your Mac. If necessary, hold your Mac's power button for several seconds to force it to power down.
Start up your Mac while holding the C key to start from the disc.
Once started from the disc, choose Disk Utility from the Utility menu.
Note: If the gray screen issue persists and you can't start from the disc, go to the "Disconnect peripheral devices" section.
In Disk Utility, perform a disk repair of your Mac OS X volume; if no issues are found, perform a permissions repair as well. If issues are found during the disk repair, try repairing again.
After the Disk Utility operations are complete, restart without holding any keys.
from here.