Which Run window do you use? Which OS do you use?Run XP to slipstream a XP SP. Unclear still: slipstream error or USB boot error. Verify slipstreamed XP first. Create a ISO file. Burn a CD. Make a test installation. Anyway: which hardware do you use? Motherboard, BIOS, USB device, USB storage size OK. i'll explain so to be clear. Under Windows XP Pro SP2 operating system: 1. I used an original OEM Windows XP Pro SP2 English CD, a yellowish one from Microsoft with hologram and all those other security things. 2. Copied all the contents to a folder named "XP" on C:\ partition. 3. Downloaded SP3 and left it in the root on C:\ partition, named XPSP3.EXE 4. Clecked Start > Run... and in that windows wrote C:\XPSP3.EXE /integrate:C:\XP and left it to be done. 5. Saved the boot image from original CD with UltraISO. 6. Added the $OEM$ folder in the C:\XP folder and with Total Commander and Winamp in $Progs, and a startup.cpl utility in $$ / Windows / system32 folder. 7. Created an answer file with the setupmgr.exe tool from the CD and saved it and renamed it in WINNT.SIF and put it in the I386 folder. 8. Using Nero Burning Rom, I burned all those files in the C:\XP folder onto a new CD, made it bootable with the boot image extracted with UltraISO. All of these were made under the Windows XP Pro SP2 operating system, not Vista, not W 7 nor '98, and it was made about 2 years ago. I didn't use any other tool, no nLite, no updates were included, nothing else at all. I used that CD for 2 whole years at the installation and I neved had a problem. Everytime the installation and the os newley installed worked very very fine. Now I've decided to put it on an USB stick because it intalls a lot faster so I didn't want to use too many tools, bit this one from here. Was tested on 2 different systems and I always had the same problem. Now it's more convenient for me to test it on a Asus P5N-E SLI MB, BIOS 0703, CPU E2220 2,4Ghz, 1G RAM, 80G Western Digital ATA, VGA Asus EN6600. The USB stick, is an Silicon Power of 16Gb, and I also used an Kingston DT400 of 4Gb - same problem with both of them. I didn't even renamed the partition on the USB stick. I left it blank.