ran bios; memory ok; hard drive quick test/smart test passed
checked error log - code was 305
tried recovery manager boot to earlier time - got error message about corrupt files
blue screen error stop: 0x00000f4 (0x0000000000000003, 0xfffffa8006bdbc10, 0xfffffa8006bdbe48, 0xfffff800024f3540)
have no os recovery disks - best to obtain, then try booting from disks?
or other suggestions?

thanks

I don't think simply getting a recovery disk will solve this issue. 0xF4 error usually points at hard drive issues, so you may need to replace that hard drive.

Please check what is the make/model of the drive in question, download appropriate diagnostic tool from its manufacturer's site, and thoroughly test that drive. If you can't do that, other tools which you can use to do so include test disk. Regards