These are the games I KNOW can work on flash drives without useing disks. They run faster off the flashdrive than YOUR harddrive. Can work on all PCs that meet the system requirements of that game (minus the CD/DVD rom speed) All you have to do is coppy the whole folder to your flash drive.

Unreal (Anthology Edition)

Unreal Tournament (Anthology Edition)

Unreal II (Anthology Edition)

Unreal Tournament 2004 (Anthology Edition)

The Ultimate Doom (Doom Collector's Edition)

Doom II (Doom Collector's Edition)

Doom III (Doom Collector's Edition)

Quake (Quake Collector's Edition)

Quake II (Quake Collector's Edition)

Quake III Arena ( Quake Collector's Edition)

Add more if you know of any!