unable to bootscan I have xp any suggestions
Welcome to the forums, userman! 
A little more info would be helpful … any error messages, Home/Pro version, other symptoms, etc? ???
How are you trying to initiate the boot-time scan ?
I have free version avast 4.6 home edition, bootscan starts on restart but will not complete and goes straight to desktop.
What exactly does it mean, “will not complete”? What happens?
keyboard error unable to complete scan press esc to bypass scan, Iignore this instruction and scan is bypassed anyway
OK. What operating system do you use? What keyboard - USB or PS/2?
Also, check the folder \Data\Log, please - there should be a log file (called something like asBoot.txt). What does it contain?
I use usb keyboard
It is likely that you will need to enable USB devices during Boot in your systems BIOS for your keyboard to be recognised outside of windows.
how do u do that
It is different for different motherboard and BIOS manufactures. If you got any documentation with your system or motherboard (I got a booklet) it should have some info on the BIOS setup.
When you boot to enter the BIOS setup before windows starts most accept tap, tap, taping on the delete key interupts the boot and enters the BIOS/CMOS setup. You will see a menu structure, I think it will be the integrated peripherals section, but you may have to look in other locations.
The problem I see here is the chicken and egg scenario, how to navigate the menu if the keyboard isn’t recognised. Some basic keyboard function may be available whilst in the BIOS setup. Good Luck.
Another alternate is to by adapters that allow you to plug-in USB keyboards/mice into PS2. My wireless USB keyboard & mouse came with these adapters. You can also find them at several computer supply companies and here is one …
http://www.tigerdirect.com/applications/SearchTools/item-details.asp?EdpNo=1220387&CatId=469