Hello
I cannot create bootable pen drive via YUMI – Multiboot USB Creator
in windows 10.
https://getfedora.org/en/server/download/
I'm trying to install the Fedora 26 Server on an old HP PC
I'm booting from an YUMI – Multiboot USB Creator and get to the Fedora Install Screen
I select "Install Fedora 26"

I get:

[ OK ] Started Show Plymouth Boot Screen.
[ OK ] Reached target Paths.
[ OK ] Reached target Encrypted Volumes.
[ OK ] Reached target System Initialization.
[ OK ] Listening on Open-iSCSI iscsiuio Socket.
[ OK ] Reached target Sockets.
[ OK ] Started Forward Password Requests to Plymouth Directory Watch.
[ OK ] Reached target Basic System.

After that it gives me a warning about starting timeout scripts and the final two warnings
Could not boot.
/dev/root does not exist

Did you follow the recommendation (on that link) to read the install guide ?.

I'm trying to install the Fedora 26 Server on an old HP PC
I'm booting from an YUMI – Multiboot USB Creator and get to the Fedora Install Screen
I select "Install Fedora 26"

I get:

[ OK ] Started Show Plymouth Boot Screen.
[ OK ] Reached target Paths.
[ OK ] Reached target Encrypted Volumes.
[ OK ] Reached target System Initialization.
[ OK ] Listening on Open-iSCSI iscsiuio Socket.
[ OK ] Reached target Sockets.
[ OK ] Started Forward Password Requests to Plymouth Directory Watch.
[ OK ] Reached target Basic System.

After that it gives me a warning about starting timeout scripts and the final two warnings
Could not boot.
/dev/root does not exist

What about what syg00 told you to do?

How old? Does it meet minimum requirements?

Yes! I had used before CentOS 7 now try to install fedora for latest PHP and Apache CentOS have 6.4 PHP

Dual core 4 GB RAM and 500GB SATA

THank you

Get a new quality flash drive and just install Fedora as it is suggested at Fedora web site. We can't rule out the oddity of YUMI or old flash drive.

rootdelay=20 parameter maybe?