Hello All, I am upgrading my daughter's computer. She had an IBM Netvista P3, 256 meg ram (max I can put in the mobo), 20 gig hard-drive. I acquired a working Compaq Deskpro EN Small Form Factor P800 10e/6/128c from an auction and added some RAM (to 512mb the max) and the computer booted ok. I replaced the existing 10gig HDD with the 20 gig from the Netvista, expecting it to boot, and received the NTLDR is missing, press any key to reboot warning. I checked on line and placed another 10gig HDD from a second working Compaq Deskpro EN Small Form Factor P800 10e/6/128c, which booted to the OS with out any problems, so I imagine the MOBO, ram, cables and ribbons etc are ok. I found this site http://tinyempire.com/notes/ntldrismissing.htm and downloaded the boot floppy. I can access the disk, the OS and all programs, but when I reboot, the message again. The site mentions ensuring the drive containing the OS is marked ACTIVE. I followed the directions, and the option is greyed out. Any suggestions on how to "activate this disk" so it will enable direct boot with out the floppy will be gratefully received. Thanks for reading Anne Smith [log in to unmask] Do you want to signoff PCBUILD or just change to Digest mode - visit our web site: http://freepctech.com/pcbuild.shtml