Bsod

at the very top of the BSoD you should have the type of BSoD, that's more helpful.

Actually, what he posted is VERY helpful - now we know the faulty driver is called "SYMEAA.SYS".

The usual way would be uninstall\rename\remove C:\windows\system32\symeaa.sys (you said you can work an hour or so without BSoD, right?). However, quick googling has shown me that the driver is related to Norton antivirus. If you are running this antivirus, uninstall it completely and re-install it (or possibly install a different anti virus if the problem occurs again even after reinstalling).