I've just installed Linux for the first time, except I installed it on a Seagate USB Hard Drive (500GB, USB 3.0, 3 Partitions: 10 GB Ubuntu/1GB swap/The Rest NTFS) from a Live USB drive (4GB) made in PenDriveLinux.
It boots perfectly on a 6/7 year old Toshiba Satellite A100 (32 Bit Celeron Dual Core 1.6GHz, 1.5GB RAM. XP on 60GB internal HDD,) a year old netbook (Acer Aspire One 722 with Windows 7 on internal 320 GB HDD, 2GB RAM and 1GHz dual core AMD Processor) and an HP Probook (2nd Generation i3 Quad Core 2.3 GHz, 4GB RAM, Windows 7 on internal 500GB HDD) but won't boot on my 6 month old Desktop (Compaq, 64 Bit 2.3Ghz Pentium Dual Core, 4GB RAM, Windows 8 on 500GB partition of 1TB HDD.) Neither computer has USB 3.0 ports. All I get is a message saying "Error Loading Operating System" after choosing the USB HDD in the BIOS menu. I can run gParted off a USB stick on both computers no problem.
I've tried with both Ubuntu 12.10 & 13.04 beta (I know its not supported here yet, but the problem is in the current version too) but nothing changed. Any ideas on how to fix this?